"Hey, what is this a sideshow?"
Bathroom Spider is an anthropomorphic talking spider in the downstairs Bigheads' bathroom that Mrs. Bighead asks Rocko to get rid of in Leap Frogs. Rocko assumes that it is a normal spider, but when Rocko goes to the bathroom to check, he sees it's like every other character in the series actually using the bathroom, it says, "Hey, what is this a sideshow?", then Rocko slams the door.
It only has one very brief appearance in Leap Frogs. It is voiced by Doug Lawrence.