Taz marking territory

I just awhile ago caught my cat taz peeing in my bunnie's{Daisy} litterbox. I thought it was kinda funny to see my big cat in a small bunny litterbox taking a piss. I quickly got my camera and took a picture cus I wanted to remember that moment. I didn't know if I should be worried or not so I called my sister and she said he was just marking his territory. She said that her cat Indy did that to her bunny. So it was nothing big to worry about. I guess that also explains why taz tried going in Daisy's cage earlier today.