Jackenstein

... VERY WELL... IF YOU COME CLOASER TO THIS PLACE...
... THEN YOU MAY FIND...
... THE DARK...
... HAS COME TO YOU!!!

Jackenstein, Chapter 4

Jackenstein (JP: ジャックシュタイン Jakkushutain) is a Darkner in Chapter 4 of Deltarune. He is a miniboss that is encountered in the Dark Sanctuary's Dark Zone. His battle introduces a new mechanic in the form of the Darkness effect, which reduces TP gain significantly. As such, it serves as a tutorial for later fights using the effect in the Chapter.

Profile

Appearance

Jackenstein is a tall and burly figure with a large upper body, towering over most of the characters by a considerable margin. His body is an off-white color, with various pale green markings spread throughout his arms and upper chest. There are four circular orange patches that appear to be sewn onto his body; one on each shoulder, and one on either side of his chest. His torso bears a pattern resembling a skull, with the patches on his chest as its "eyes", a dark triangle below them as the "nose", and a curved stitch below it as a "mouth". He also has a thin, short tail that ends in a bright orange ball.

Jackenstein wears a black and orange mask on his head, which resembles a jack-o'-lantern. A pair of screw-like horns stick out of the top of the mask, and what appears to be a few strands of hair stick out between them. The mask is able to emote like a real face, allowing Jackenstein to open his mouth or blush through the mask. Its eyeholes are also able to glow orange, as seen during Jackenstein's battle. Jackenstein wears the mask to hide his true face, which resembles a small candle with ears, a single antenna, and black dot eyes.

With the screw-like horns and the sewn-on patches on his body, Jackenstein resembles various popular depictions of Frankenstein's monster, particularly his appearance as portrayed by Boris Karloff in the 1931 film Frankenstein. Frankenstein's monster is a common sight in Halloween decorations and merchandise, furthering Jackenstein's Halloween theme.

In the Light World, Jackenstein is an orange jack-o'-lantern stored inside of the church's closet. It rests on top of a black coat sitting on a brown chair. Susie assumes he is a Halloween decoration stored with "other creepy stuff".

Personality

Jackenstein is kind and playful, despite his attempts to appear scary. He hides his face due to being bullied for his "LARGE AND UGLY BODDY", and appears lonely as a result, trying to deter other people from entering the Dark Zone and coming close to him. Jackenstein has an aversion to light, preferring to stay in darkness.

After Jackenstein is defeated and healed, he is eager to help the party and moves out of the Dark Zone, though he still seems nervous about meeting other people.

Speech pattern

Jackenstein speaks in all uppercase letters, and frequently misspells words, where he replaces existing vowels or adds additional ones. His misspellings often align phonetically with the correct spelling of the words. His dialogue is frequently written using ellipses, implying a drawn-out tone.

Etymology

Jackenstein is likely a portmanteau of "jack-o'-lantern" and "Frankenstein", his two main visual inspirations.

Main story

Jackenstein hugs the party, as Fireplace plays

The party encounters Jackenstein after a piano puzzle leading to the Dark Sanctuary's Dark Zone. Moving towards him makes him complain about the light and warn the party to not come closer. As the party progresses, the room's light continuously dims until their surroundings become pitch-black, at which point Jackenstein confronts the party. After defeating him, the light is turned back on; scared, Jackenstein attempts to run away and hits his head on a chandelier. Ralsei unsuccessfully tries to heal Jackenstein's resulting headache, but only Susie's healing magic ends up helping him. Jackenstein then thanks Susie and hugs the heroes, declaring them to be his "FRAINDS", and gifts them the ClaimbClaws.

Jackenstein is later found in the Old Man's study, having escaped the Dark Zone, where he is sweeping the floors in exchange for tea. The party can talk to him to receive directions.

After the Dark Sanctuary Fountain is sealed, Susie and Kris can find Halloween decorations in the Light World, stored in a closet in the storage room of the church. Susie recognizes the decorations as Jackenstein's Light World counterpart.

Jackenstein helps the party climb a tall tower

Before facing the Knight atop the tower in the 3rd Sanctuary, Jackenstein appears behind the party to assist them in climbing after the bottom part of the tower is destroyed. The Knight continues to shatter sections of the tower until Jackenstein falls off. If at least one Darkner was recruited and none were LOST, a group of Cuptains and recruits appears and lifts him back to safety along with the heroes. If any recruits were LOST, the party climbs off of Jackenstein as he falls to the ground, presumably dying in the process, which angers Susie.

As of Chapter 4, Jackenstein cannot be brought to Castle Town, as Susie deems his Light World counterpart too big to be carried at the moment. She plans to retrieve him at a later point.

Creation and development

The character of Jackenstein, including the way he speaks, was likely based off of a poem that Toby Fox created at the age of 5 for his mother and shared on social media in the months prior to the release of Chapter 3 and 4. The poem in question mentions a "big pumkin" and a "little pumkin", which may refer to Jackenstein and the small dancing pumpkins. Additionally, it mentions the pumpkin being scary, which was what Jackenstein was banished for. The third line of the poem reads "pumkin fall off the wall", which is what happens to Jackenstein during the wall-climbing cutscene.

In battle

Attacks

Jackenstein's attacks, unlike other enemies, feature different mazes that appear like haunted houses. The objective is to collect a key, then go to the exit that opens up after doing such.

Collecting the key grants 5% TP. The mazes also contain "TREASURE", which grant 1% TP when collected.

After grabbing the key and reaching a specific point in the maze, Jackenstein's pumpkin appears and exclaim that "YOUR^[sic] TAKING TOO LONG", before chasing the SOUL. The SOUL, and often other obstacles, also gain a significant increase to movement speed. If the jack-o'-lantern catches up to the SOUL, it will begin dealing rapid contact damage. The turn will usually end after the player either reaches the exit or the jack-o'-lantern deals enough damage. Aside from the different jack-o'-lanterns, the mazes often feature moving or static pumpkins and eyeballs as the main hazards.

If the ScaredyCat ACT was used on the previous turn, the SOUL starts at the faster speed, the jack-o'-lantern's message is significantly shortened so that it starts chasing sooner, and movement is not disabled during the message. There is no additional SOUL speed-up after it appears.

Attacks also end after 999999 frames (about 9.26 hours) if not escaped normally.

When Kris uses the Unleash ACT, the "Unleash" attack is used on that turn. Otherwise, the attacks always occur in sequence, giving the first one that has not been encountered yet.

Starter

Starter maze

A simple two floor, five room layout. It has 6 Treasure, and the Key at the center of the second floor. The SOUL appears at the bottom left side, and the exit is on the far right.

It has no hazards, and the pumpkin does not appear.

The interior resembles a regular house with two dining rooms, and the far left room resembling a dungeon.

3x2

3x2 maze

A clock-themed, six room layout with two floors. It has 13 Treasure and the Key at the top right. The SOUL appears at the bottom right, which is also the exit.

The jack-o'-lantern appears, saying "YOUR TAKING TOO LONG", upon reaching the bottom left with the Key, and travels from the top right, to the top left, then down to the bottom left, and finally right to the exit. If ScaredyCat is used, the voice line is significantly sped up.

Normal

Normal maze

A vertical-focused layout which forces the SOUL into tight corridors with various obstacles. It has 9 Treasure. The enemies in both central layers move clockwise, encouraging the player to follow that flow.

The jack- o'-lantern appears, saying "YOUR TAKING TOO LONG", upon reaching the top right with the Key, and travels from the top left, quickly moves to the top right, then slowly moves down to the exit. If ScaredyCat is used, the voice line is significantly sped up.

Chimney

Chimney maze

The bottom left enemy moves slowly, bouncing off the walls. The top left and top right enemies move in a wavy pattern with a different wave for each dimension. The enemies in the center of the decorative circles are stationary.

The jack-o'-lantern appears upon reaching the bottom right (where the EXIT is) with the Key. However, it appears from the exit, and the exit gets blocked off, instead revealing the chimney in the top left as the exit. If ScaredyCat is used, the voice line is significantly sped up.

The chimney is always open and can be used to leave the attack, even without collecting the key.

Too Long

Too Long maze

A tower-like layout with lots of gaps the SOUL can maneuver through. The background decor is visibly stretched here.

The large enemies in the center of the row move slowly back and forth, while the small ones move in a counterclockwise fashion around the row.

The key in this layout is stretched horizontally. After the key is collected, the SOUL becomes much wider than usual, making it unable to fit through small gaps.

The jack-o'-lantern appears above the box, saying "YOUR LONG", shortly after collecting the Key. The jack-o'-lantern becomes very wide (such that it can reach the entire battle box) once it says "LONG", and it moves slowly down. If ScaredyCat is used, it says "LO NG" and is significantly sped up.

No Pumpkin

No Pumpkin maze

Square layout with a grid structure, featuring various obstacles in some areas. There are various background symbols scattered throughout the grid including crowns, chess pieces, a sword, and a flower. The jack-o'-lantern does not appear in this maze layout.

Two Pumpkins

Two Pumpkins maze

Square layout in a path structure. The background decor features three snake-like creatures squished into the layout.

The center enemies have Treasure trailing behind them, which move alongside their horizontal movement.

A pumpkin with a smiley face, saying "YOUR TAKING TOO LONG" in a more lighthearted way than usual, appears upon reaching the top left with the Key. Instead of speeding up movement as normal, it instead slows down movement. Additionally, it halts if it gets near the SOUL, acting as a wall rather than damaging the player. The movement pattern starts from the top right and follows the path to the exit, but moves very slowly.

Shortly before reaching the bottom left, the normal jack-o'-lantern appears, saying "YOUR TAKING TOO LONG IS TAKING TOO LONG" with the first "YOUR TAKING TOO LONG" said in the same voice as before. It then begins chasing the SOUL as usual, following the same path as the pumpkin with the smiley face, but at a much faster speed. If it collides with the smiley face, the smiley face blows up.

If ScaredyCat was used, the smiley face only gets to the "YOUR" part before the usual jack-o'-lantern appears, immediately exploding the smiley face and saying "YOUR TAKING TOO LONG" as usual.

Your Tutu

Your Tutu maze

A large, maze-like layout with the paths set up diagonally. The layout is themed around buried objects and includes many skeletons buried into the walls.

The key in this attack is textured to look like a tutu, but acts like usual. When the tutu is collected, the SOUL wears the tutu, with it following the SOUL's movement. Additionally, the wall to the left of the starting area is removed.

Right before returning to the starting area, the jack-o'-lantern appears, saying "YOUR TAKING TOO TOO". While escaping, the SOUL drops the tutu midway, which gets picked up by the jack-o'-lantern. The jack-o'-lantern speeds up after reaching the maze's bottom path leading to the exit, and places the tutu back on the SOUL when reaching it, shyly saying "YOUR TOO TOO". It will then seemingly leave to the left, but after the player gets closer to the exit it starts moving rapidly back toward the right.

If ScaredyCat was used, the voice line is replaced with "TUTU". It returning the tutu to the SOUL and leaving plays as normal, although the SOUL is fast enough to escape before being caught.

Final Maze

Final maze

A massive linear layout consisting of a gauntlet of ghost bullets that fly in elaborate patterns throughout the layout.

Shortly after obtaining the Key, an indefinite amount of small jack-o'-lanterns appear, each saying "YOUR TAKING TOO LONG", from the top right, with each one trailing behind the last as they quickly move to fill the maze. The SOUL also does not speed up after the pumpkins appear in this attack.

If ScaredyCat was used, the voice line simply says "LONG", but the text actually spells "LONG TAKING TOO LONG".

Bullet Rain

If the player has completed all mazes without having reached Jackenstein's maximum MERCY, the SOUL is instead trapped in a rectangular box with projectiles and Treasure raining from above. This is the only attack Jackenstein will use for the rest of the battle.

Unleash

This attack is used on the turn after Kris uses Unleash.

The SOUL emits a powerful light, with the jack-o'-lantern commenting "YOUR TOO BRIGHT" upon contact on the ACT's first use. The SOUL can then be used to chase the pumpkin head as it panics around, saying "MAMMA MIA" in varying pitches while in the light's range.

Jackenstein's MERCY meter rises whenever the jack-o'-lantern is in the light, going up to +35% MERCY per use of Unleash. Upon reaching 99%, it moves extremely quickly in a desperate attempt at evading the light, ending up in the light by itself shortly after.

Strategy

Jackenstein cannot be attacked; all attacks miss. As such, he must be spared by getting to 100% MERCY. The only way to raise the MERCY meter is to use the Unleash ACT for 60% TP, which grants 35% MERCY over the course of the following attack.

As of v1.03, losing to Jackenstein a second time halves the damage the chasing pumpkins deal. Losing a third time causes TP gain to be increased by 50%.

• This battle takes place in Darkness, reducing TP gain from normal means.
  • Instead, the recommended way to gain TP is through collecting the Treasure and keys that are present inside the attacks.
  • Although significantly weaker than normal, DEFEND still grants a small amount of TP, making it a good default option.
  • TP-increasing items are unaffected by darkness, making them able to significantly speed up the fight.

• This battle provides several ACTs to assist in navigating the mazes and collecting the Treasure:
  • Susie's TreasureHunt ACT costs 2% TP, and gives the SOUL a magnet effect, allowing it to attract any nearby Treasure. While the range may not be very big, with TreasureHunt, you do not have to touch the treasure to collect it. TreasureHunt can allow collecting treasure through walls if they are close enough to it.
  • Ralsei's LightUp ACT costs 1% TP and increases the range that the SOUL emits light in. This can be useful to make it easier to learn the maze's layout and see obstacles.
  • If the player has a Chapter 4 SAVE file that has encountered Jackenstein, Kris gains access to the ScaredyCat ACT. It costs 2% TP, increases movement speed, and reduces defense for that turn. It allows navigating through the maze more quickly, but it does not make the attacks noticeably easier as increased speed can result in more mistakes. Due to the pumpkins being based on location, using ScaredyCat to finish mazes faster does not help evade them.

Healing items are preferable over Ralsei's healing in order to conserve TP.

Despite the claim that the player is "taking too long", the jack-o'-lantern chase only begins after the player has collected the maze's key/tutu, so it is possible to collect all the treasure and map out a route from the key to the exit, without time pressure.

Without items, perfect collection of Treasures and constantly DEFENDing will gather enough TP to finish the fight right before the last maze.

Quotes

Pre-battle

• ... LAIGHT...
• ... WHO DAIRE BRING LAIGHT HEAR...
• ... GO... BACK...
• ... YOU SUDN'T COME HERE...
• ... THIS ZOAN... IS FORBIDEN...
• ... CONTINUE AND YOU MAY FIND YOURSELF SPOOCKED IN THE DARK...

• [When the party approaches Jackenstein]
  • ... VERY WELL... IF YOU COME CLOASER TO THIS PLACE...
  • ... THEN YOU MAY FIND...
  • ... THE DARK...
  • ... HAS COME TO YOU!!!

Battle

• [First Maze]
  • ... GHO HO HO... THERE'S NO ESCAIPE FROM THE [DARK ZONE]
  • UNLESS... YOU LEAVE
• [Second Maze]
  • ...GO BACK... ... YOUR TAKING... TOO LONG...
  • YOUR TAKING... TOO LONG...!!!
• [Third Maze]
  • WHAT THE HEACK WAS THAT PUMKIN THAT WAS SCAIRY!!!
  • JUST KIDDING THAT WAS MINE : )
• [Chimney Maze]
  • OH NO!!! I CAN'T FIND MY PUMKIN...!! BUT MAYBE... IT WILL FIND...
  • ... YOU
• ["Long" Maze]
  • GO... BACK... BEFORE LONG...
  • ... GO BACK!!! BEFORE LONG!!!
• [No Pumpkin Maze]
  • YOU DIDN'T GO BACK
  • : (
• [Two Pumpkins Maze]
  • NO MOIRE MISTER NAICE GUIY...
  • INSTEAD.
  • MR. VERY NAICE GUY
  • LEAVE : )
• [Tutu Maze]
  • ENOUGH!!! MY PATIANCE RUNS THIN
  • NO MORE KEYS!!! DRESS IN HUMILIATION
• [Final Maze]
  • ... FOOL THAT YOU ARE... YOU REALIZE NOT WHAT FRAIGHTFUL FOARCES AWAIT YOU...
  • TONAIGHT, ON THE MOST HAUNTED OF NAIGHTS... I SHALL INFLICT YOU WITH MY GRAITEST CURSE...
  • THE SAME THING I WAS USING THE WHOLE TIME
• [Treasure Rain, after all mazes have been completed]
  • YOAR STILL HEAR...? INTERESTING...
  • INTERESTING... BUT IT SUCKS... : (
• FINE... BE TRAPPED IN THE [DARK ZONE]... FOAREVER!!! [Treasure Rain for the 2nd time]
• [Using UNLEASH for the 1st time]
  • YOU DAIRE BRING LAIGHTS TO MY LAIRE!? HA HA...
  • IN THIS PLAICE OF TRUE DARK...
  • LAIGHT HAS NO AFFECT ON ME!!!
• [Next attack after 1st use of UNLEASH; replaces normal dialogue]
  • NO!!! THE LAIGHT!!! IT HAS EFFECTS ON ME!!!
  • STOP USING THAT!!! TEARRIBLE!!! GO TO [DARK]!!!
• [Using UNLEASH for the 2nd time]
  • NO!!! NOT THE LAIGHT!!! IT BURNS!!!
  • TO THINK MY OWN PELLETS WOULD BE USED AGAINST ME
• [Using UNLEASH for the 3rd time]
  • NO!!! THE LAIGHT!!! DON'T BROING IT CLOASE TO MY FAICE!!!

Voice lines

• YOUR TAKING TOO LONG [laughter]
• YOUR TOO BRIGHT
• MAMMA MIA [panicked gibberish]
• YOUR LONG [laughter]
• Your taking too long
• Your taking too long IS TAKING TOO LONG [laughter]
• YOUR TAKING TOO TOO [laughter]
• YOUR TOO TOO
• Your-your-your-your-your-yo-y-y-y-y-y-y-y-y-your taking too long [high-pitch laughter]

Voice lines (ScaredyCat)

• YOURTAKINGTOOLONG [laughter]
• LONG [laughter]
• Your [explosion] YOURTAKINGTOOLONG [laughter]
• TUTU [laughter]
• long [hi-pitch laughter]

Post-battle

• THE LAIGHT... NOT THE LAIGHT!!!!
• NOOOOOOO!!!
• N... NO... DOAN'T LOOK... I'M... I'M...
• I'M TOO SCAIREY!!!
• [Ralsei] Are you all right? The chandelier... It...
• OUCHI... OHHH, IT HOARTS... IT HOARTS...
• EVERYTHING... SO BRAIGHT... CULDN'T SEE...
• HEAD HIT SHANDALIERE...
• [Ralsei] We're sorry, we were just looking for a way...
• OH... MY HEAD... IT HOARTS... IT HOARTS INSIDE
• [Ralsei] Um, don't worry! We know how to use healing, so...
• HMM...
• OAAAHHHH IT STILL HOARTS!!!!!!!!!
• [Ralsei] H-huh? Sorry, I guess I'll, um, try it again...!
• [Susie] Umm, maybe I could...
• [Ralsei] Susie...?
• [Susie] Umm, nothin'. Nevermind.
• [Ralsei] How's this? Feel better?
• NO... STILL HOARTS...

• [After Susie heals Jackenstein]
  • OH!!!! THE OUCHI... THE HOART... IT'S GONE!!!
  • [Ralsei] ... Susie?
  • [Ralsei] Susie, that was a great idea!
  • [Susie] H-huh?
  • [Ralsei] I was wondering why my healing wasn't working...
  • [Ralsei] I suppose... I was only healing the outside.
  • [Ralsei] But Susie, your healing blast seemed to hit the spot!
  • [Susie] Huh?
  • [Susie] Well, heh, I was uh, actually just trying to heal that old man...
  • [Ralsei] ... Old... man?
  • [Susie] Yeah, he's...
  • [Susie] ...
  • [Susie] Huh. Guess he left. Heh.
  • [Ralsei] Well, Mr. Jack is better, so let's be on our way!
• [Talking to Jackenstein again]
  • YOU... GIRL... YOU HELPED ME...
  • [Susie] Hey, it was, uh...
  • YOU THREE... MY FRAINDS!!!
  • ME NAME IS JACKENSTEIN.
  • I WAS BULLYED, AND HAITED BY THE OTHERS, FROAM MY LARGE AND UGLY BODDY.
  • I WAS BANNISHED TO THE DARK ZONE, ONLY TO APPEAR ON FESTIVAL NAIGHT...
  • I WAIR THIS MASK, BEACAUSE MY TRUE FAICE, SCAIRES EVEN MYSELF.
  • DID YOU
  • DID YOU WANNA SEE IT
    • ["Yes"]
      • COVER YOUR EAYES...
      • [Ralsei] Umm, actually, it's kind of cu--
      • ACTUALLY IT'S TOO SCAIRY
    • ["No"]
      • YES. ME NEATHER.
    • THE POINT IS... YOU THREE... ARE MORE DIFFERENT, THEN THE OTHERS.
    • YOU ARE KAIND. MERSIFULL. AND, MOAST OF ALL...
    • YOU DOAN'T KNOW HOW TO CLAIMB.
    • TAKE THIS... MY FRAINDS... MY CLAIMBING SET.
    • IT'S TOO SMALL FOR ME
  • YOUNG WOMUN... THAINK YOU FOR THE WONDERFUL HEALING.
  • [Susie] Hey, it was nothing.
  • LET ME KNOW IF I CAN EVER REPAY YOU...
  • I LIVE IN A HOAL

Flavor text

• [Check]
  • An unsightly beast that lives in total darkness.
  • Gather TREASURE to gain TP, and use "UNLEASH" to light him up!
• [Check, subsequent uses]
  • You CHECKed Jackenstein... You remember that DEFENDing gives you TP!
  • You remember Susie and Ralsei might have their own ACTs as well...!
• Ralsei lit up! The light grew larger and stronger! [LightUp]
  • Ralsei lit up! Light grew! [On repeat]
• Susie sniffs out treasure! It's easier to pick stuff up! [TreasureHunt]
  • Susie sniffs out treasure! [On repeat]
• Darkness constricts you... TP Gain reduced outside of TREASURE! [Encounter]
• You are in the DARK ZONE. [Neutral]
• The atmosphere feels tense... [Neutral]
• The atmosphere feels tense... (You can use UNLEASH!) [Neutral, upon reaching over 60% or more TP]
• Kris's SOUL emitted a brilliant light! [Upon using UNLEASH]
• [ScaredyCat]
  • Your heart pumped nervously!
  • SPEED increased for 1 turn!
  • Everyone's DEFENSE down!
    • Scared! SPEED up, DEF down! [First repeat]
• Too dark to see near the walls. There's something miniboss-shaped in here! [Neutral]
• Too dark to see near the walls. There's something very Susie-like in here! [Neutral]
  • [Susie] That's ME, dumbass!
• Too dark to see near the walls. There's something fluffy in here! [Neutral]
  • [Ralsei] K... Kris?
• Too dark to see near the walls. There's a texture of a dog playing maracas in here! [Neutral]
• You can imagine Berdly in your head warning you about Grues. Smells like rotting fruit. [Neutral, if Chapter 2's Weird Route was completed, 3% chance]
• Too dark to see near the walls. [Neutral]
• Too dark to see near the walls. There's a pit here! [Neutral]
• Everything seems OK. [Neutral]

Gallery

• 
  Jackenstein's eyes glowing in the dark
• 
  Jackenstein talking
• 
  Jackenstein clutching his head
• 
  Jackenstein scared
• 
  Jackenstein covering his face
• 
  Jackenstein running away
• 
  Jackenstein hugging the party
• 
  Jackenstein lifting his mask to reveal his real face
• 
  Jackenstein cleaning in the Old Man's study room
• 
  Jackenstein upon being interacted with in the Old Man's study room
• 
  Jackenstein blushing
• 
  Jackenstein climbing the tower with the party on his shoulders
• 
  Dancing jack-o'-lantern

Trivia

• The dialogue in Jackenstein's fight includes numerous refences to lines from Ganon in Zelda: The Wand of Gamelon that are known for their use in YouTube Poops.
  • The line "YOU DAIRE BRING LAIGHTS TO MY LAIRE!?" is an almost verbatim quote from Ganon in his pre-battle cutscene in The Wand of Gamelon.
  • The line "NO!!! NOT THE LAIGHT!!! IT BURNS!!!" references Ganon's post-battle cutscene in The Faces of Evil.
• Jackenstein's line "YOU SUDN'T COME HERE" is (mis)spelled almost exactly the same as a line in the video adaptation of the fanfiction Half Life: Full Life Consequences.
• The phrase "Too dark to see near the walls." that recurs in Jackenstein's flavor text is a reference to a line of narration from the game Brandish. This line was previously referenced in Undertale when inspecting the walls in Alphys's lab before the lights are turned on. Though the line is rather generic, Legends of Localization Book 3: UNDERTALE confirms that the Undertale narration was specifically intended as a Brandish reference, meaning the similar line in this battle is almost certainly a reference as well. This referenced dialogue is from an area in Brandish named Dark Zone, which is also the name of the area Jackenstein is fought in.
• The line "Too dark to see near the walls. There's a pit here!" may be a reference to the Edgar Allan Poe short story, The Pit and the Pendulum.
• The line "YOUR TAKING TOO LONG" and the jack-o'-lantern's color could be a reference to the Strong Bad Email episode "video games", in which Strong Bad imagines a video game featuring a red-and-black version of his face that speaks in similar broken grammar (i.e., "YOUR HEAD ASPLODE").
• The flavor text "You can imagine Berdly in your head warning you about Grues." is a reference to Zork, an early text adventure game.
• The screams of fear used during the Unleash ACT reference Mario's recurring "Mamma mia" line from Super Mario 64.
• The red pumpkin prominently featured in Jackenstein's attacks can be found outside of battle, seemingly existing as a separate Darkner.
• After the third maze, small, orange dancing creatures with pumpkin heads will begin appearing, sliding from right to left above the party's health bars. This is only cosmetic, and does not affect the fight.
  • These creatures first appeared in a Bluesky post made by Toby Fox for Halloween 2024.
• Jackenstein's attacks may be a reference to the Atari 2600 game Haunted House, or the game of the same name for the Magnavox Odyssey.
• The mechanic/idea of a smiling jack-o'-lantern chasing the SOUL through a maze of bright neon walls for taking too long is likely a reference to the 1980 Stern Electronics arcade game Berzerk, in which an indestructible bouncing smiley face enemy named "Evil Otto" begins to pursue your character when you take too long to exit any given room. The reference is made all the more apparent in the attack featuring the "Two Pumpkins" maze, wherein the first jack-o'-lantern's face strongly resembles that of Evil Otto.
• In the PS4/PS5 versions, an achievement can be earned if more than 110 TREASURE is collected during his battle.
• Holding SPACE after using Unleash shows the hitbox of the light glowing from the SOUL. This is likely a debugging feature.

Version history

Game edition	Version tag	Changes
Deltarune Chapter 4	v1.03	If Jackenstein is lost to two times in a row, the chasing pumpkin's damage is halved. The third loss causes the TP gain to be increased by 50%.
		Fixed a softlock where the ScaredyCat ACT can cause the SOUL to outpace Jackenstein's pumpkin as it tries to return the tutu.
	v1.04	Reduced the speed of the bullets on one of Jackenstein's attacks.