What was that show on nickelodeon in the late 80's?

It was a skit show. kinda like SNL but for kids. Alanis Morrisette was on it and she was a kid then. Everytime anyone said I don't know, green slime came down on their heads! It wasn't double dare. It was not a game show. It is driving me batty! I watched it ALL the time but I can't remember the name!