Instead of the heart lockets, MK, Frisk, and Asriel gave each other friendship bracelets! like what UT undyne jokingly says during her cooking lesson.

My headcanon for how this battle would work is that it’d be sideways similar to Deltarune battles, and you have to dodge Monster Kid’s fire breath.

In general I wanted to refrain from using rainbows and stars because I consider that Asriel’s motif. So dragon Monster Kid it is! MK probably idolised their adoptive parents a lot and thought fire magic was the coolest thing ever.