> The parents are always saying, "isn't he funny" while the kids are terrified of the huge blood-red mouth.

Sounds like a real cliched clown. I've always thought circus clowns were very funny, especially when they let circus animals get the better of them.

If you're looking for scary ones though you can't go past the hardcore hiphop outfit, the Insane Clown Posse (www.insaneclownposse.com); I mean, they tick all the boxes, they're clowns, they're insane, and in a posse.
Then of course there's the 7th memeber of the band Slipknot who has an evil clown theme. Clowns and horror (and music apparently) mix very well. There are, of course, countless films which include weird or violent clowns. One very strange addition of late to the group of children's party guests from hell was the man-bunny rabbit in Donnie Darko (brill' film, btw).