Don’t know if these have been brought up yet, but there were many of them. They began: “What’s grosser than gross?” When your audience said they didn’t know, you offered them a disgusting situation.
The only one I remember off the top of my head is:
What’s grosser than gross?
When you’re eating a bowl of Frosted Flakes and your brother says he can’t find his scab collection.
Very popular in Olympia, WA during the 80’s