Here's an easier way to catch the bunny in the basement. Chase him to one of the two dead ends where he goes (the entrance to the desert level and the place where the Mushroom man is) and run at him. Watch the exact route he takes to get away. Then, chase him back to the same place. This time, stand in the spot where he runs to and walk slowly towards him. He'll run straight at you, if you get it perfect he'll bump right into you. Just puch and you'll pick him up. This works in either dead end, but you have to be pretty accurate, but it is still much easier than diving at him.