Creepiest Cartoon you've watched?

In terms of visual levels of gross creepy, its a toss between Rugrats, spongebobs "gross up-close ups", and anything from Ren and Stimpy. In terms of thought levels of creepy, its spongebobs suicide jokes. Having your characters beat the living snot out of each other is one thing, having them try to kill themselves is a whole nother beast entirely.

Ever seen Doug "Nostalgia Critic" Walker's review on Nicktoons? He mentions that Rugrats can be insane.

Ouch, that sounds like a really creepy show. I think I'm glad that I've never seen it.

Yeah, "Ren & Stimpy" never was my thing either. God, what a vile show that was!

Shakespeare: The Animated Tales - Macbeth

"Hence, horrible shadow! Unreal mockery, Hence!"
Contains some seriously unsettling imagery, to the extent of giving even Roman Polanski's infamous 1973 live action bloodbath a run for it's money.

I'm surprised it wasn't mentioned here, but Maxwell Atom's "Evil Con Carne" was probably the creepiest cartoon show i've ever watched. Just hearing the stomach talk and seeing a brain with eyes getting stomped on a lot in one episode was really creepy and disturbing to me to watch :/

I remember , as a child, watching the Tom and Jerry cartoon The Two Mouseketeers, where , at the end, it was implied, but not actually shown, that Tom was executed when the guillotine blade fell.That one scene pretty much creeped me out.

And I so agree.

That cartoon has actually been used as a prime example of the sick bias, that it seems like the creators had against Tom and towards Jerry. They were all supposed to be on the same side (they ere all employees of the same king), but since Tom was a cat and Jerry and his even more annoying little friend were mice, they had to get him into trouble, even if that meant that he was executed. And yeah, we were still supposed to dislike Tom and like Jerry and whatever-his-name-was. Incredible...

Yeah, that would be him.