LOL I have one too and her name is Pearl. Whenever she hears the sound of litter being scratched, she tries to hide by the litter box and ambush which ever cat has just used it.

I have covered litter boxes and I last night I caught her with her head inside the litter box while poor Starr was trying to do his business. I picked her up and told her not to do this because he needs his privacy. I don't think that she got the message though. LOL