Hugga Wugga, Sweetums on occasion, lots of acts in Muppet Weird Stuff ("All Of Me", "Hugga Wugga", "You Do Something To Me", "I've Got You Under My Skin"), I think possibly Gorgon Heap too.
Worst one has got to be the Letter E from Sesame Street's Letter of the Day. I always changed the channel or turned off the TV when that came on. Something about the blond hair, the tiny eyes and lips, and the squeaky little voice by Richard Hunt. That letter E gave me one nightmare that I remember to this day (because I thought it was real and ran into my parents' bedroom). I turned over in bed, and there was that E (though I think it had buttons on it like a calculator) and it said, in a low, male voice, "Good night pal. Poison dreams." And I ran out screaming!
Just thought I'd share that with you. I'm going to go hang my head in shame now.
David "Gorgon Heap" Ebersole