Ghouliday is the 40th track in the Undertale Soundtrack. It is a re-iteration of Jingle Bells, with all of the lyrics replaced with a "oo" sample. It is on the third CD found in Napstablook's house. The song continues playing after exiting their house. This can trigger an event where the protagonist encounters Aaron and Woshua, who are too scared to fight due to the spooky music. It consists of a single sample.