Crystal
Crystal (JP: クリスタル Kurisutaru) is a deceased Lightner in Deltarune. She is the late mother of Snowy and wife of Snowy's father.
Crystal is never seen alive in game. Her gravestone is shaped like a snowflake and features a snowflake emblem at the center. A pink flower is placed on the ground in front of her grave.
Not much is known of Crystal's personality, but she is stated to have been a "proud mother" on her gravestone.
Crystal's gravestone is situated in Hometown's graveyard, in between Gerson's and Muttler's. Kris can visit the gravestone at any point that they are allowed to explore Hometown.
In Chapter 4, Snowy and his father are seen visiting Crystal's grave. When talking to them, they politely ask Kris to leave them alone.
In Undertale, the mother of Snowdrake appears as an Amalgamate in the True Lab. Originally having "fallen down", she melted and fused with other monsters as a result of Alphys's failed experiments. She is not properly named in game.