I'd like to get Mewtwo involved in this, because a) he's not the type to do anything amusing while unaffected and b) he's silly when affectionate and it's funny. Lovestruck Mewtwo acts kind of like your cat when they're goofing around trying to get you to pet them, jumping and running around and headbutting your leg, but with a lot more "look at me I am STRONG and PSYCHIC and SHOWING OFF be impressed" involved.

Come at me, anyone who wants doofy non-romantic monster love.