I had heard the Boogyman hyped up before I saw the episode, so I was kinda dissapointed.
Anyway, I'm not going to say he's the scariest, but back in the day I remember being just a little scared of Doctor Claw, mostly because not only did they never show his face, but they never showed anything else about him, either. Was he even human? Why does he have that creepy, modulated voice? Why did they not show his face? Was it too scary for children's television?
Of course, there had to be that terrible action figure and the stupid movie to show off exactly what he looked like, but I like to pretend they don't exist.