I grew up in an era when childrens' TV shows were generally what I called "propaganda for being good." It was the old idea that children's entertainment should include moral instruction. Even so kid's shows sometimes had a regular character that didn't behave well.
Rules:
One character per comment. Name both the character and the show.
I'll start with the obvious, Froggy the Gremlin from the Buster Brown Show with Smilin' Ed McConnell, later Andy's Gang.


Comments: 31
If I recall correctly, wasnt Clarabell on Howdy Doody always getting into some sort of mischief?
Charles, you never come see ME anymore!
Yeah. Uh huh.
I loved Capt'n Kangaroo!
I would have said Mr. Moose.
Remember the ping pong balls?
Grumpy Smurf?
(I hated the Smurfs, but they were everywhere. Kind of like Reagan voters.)
Felix the Cat,
The wonderful, wonderful cat!
Whenever he gets in a fix,
He reaches into his bag of tricks!