In the game's demo as well as full version prior to patch v1.001, an unused song by the name of "grandpasemi.ogg" could be found in the game's files. This was likely intended for a cut character that could have been related to Sans, Papyrus, and possibly even W.D. Gaster, due to the name Semi being based on Semi Serif fonts. It is a short, slowed-down, and re-instrumentated version of the song Metal Crusher, which is used as Mettaton's first battle theme.

This same song is now used as of patch v1.001 when you deny feeding Temmie any Tem Flakes. It plays while Temmie makes a unique facial expression, with a text graphic appearing beside her that says "can't blame a BARK for tryin'...", immediately followed by Temmie trying to attack you with her extendable arm.