Workshop link:

Monstro found Mom's Lipstick while hopping around the basement one day. With it, he could finally express her inner self. Of course, she ate the lipstick because she has no arms to properly apply it, so you gotta give her an A for effort. Isn't she beautiful?

This mod replaces the sprites of Monstro into a genderswapped version named Monstra. Don't ask me why I did it. I may or may not make more genderswapped sprite sheets in the future.