cross was walking through the omega timeline, a place where both monsters and humans were found, after he was brought there by dream sans and core frisk.

he sat down under a tree, pulling his hood up, looking at some kids playing thundersnail.

Little did he know there was a cat in the tree he was sitting under, and not just any cat, a shape shifter. You. and you were quietly watching him out of curiosity. Before deciding to jump down onto his head, out of boredom, making him groan in surprise and annoyance.