It was actually the Grim Adventures of Billy & Mandy. Mandy entered a beauty pagent to prove Mindy wrong about something. The only way she could win was to smile, but her smile caused the whole of reality to unravel. Then Grim, Billy & Mandy wake up as the Powerpuff Girls.
http://www.youtube.com/watch?v=XSrkGjSMImk
Tell me, what does Dracula say at about 1:53? After the guy pinning him down says "I see a blood sucking demon"?