The Haunted Mask was a one hour premiere for the series, and I believe it aired at night on FOX (rare for FOX's kid's programming to be shown at night) on Halloween weekend. R.L. Stein appeared at the intro and ending, sort of like the Crypt Keeper, but he didn't appear in any other episodes after that (unless you count him in the opening credits, but I think that's an actor).
The episode itself was one of the more creepy episodes of the series, with a mask that grew onto the wearers face, and these creepy floating other masks. The whole series is on Netflix, The Haunted Mask is sorted out of order in "season 5" which is actually all the two parters bundled together.
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There was a gross out parody series called "Gooflumps" that traded scares for boogers, farts, pee, and barf. I read one as a kid and it was really fucking weird. Like... I felt like I was reading fetish porn due to the gratuitous use of gross out gags. I guess it was meant to make kids laugh, but when a book is all about farts and barfing... I have to wonder if the author was just getting off on writing about that stuff.