Lappy is a character in Astral Chain. He is the mascot for the police force on the Ark. Marie Wentz often wears his costume, but the protagonist can play him in certain parts of the game as well. His birthday is listed as May 4, 2076.
Marie Wentz wears the Lappy costume most of the time. She believes that no one (aside from her and the protagonist) realizes that she's under the costume. In a blue quest as one point in the game the protagonist has to wear Lappy's costume and perform Marie's duties in her stead. Talking to other characters during this quest shows that other officers know that Marie is usually under the Lappy costume.
Lappy appears as a Spirit in Super Smash Bros. Ultimate.