I have a big, fat, mean tabby. She can't lug her big butt up onto the top of the main tank, but she can jump from the cat house thingy to the small tank. It has a black plastic hood (eclipse system) and when she lands on it, it creaks. Then as she walks I hear it creak with each step! That's about when I stop laughing and yell at her!
I put her on a diet, but she's still a big, fat, mean tabby.