Most horrifying moment in an anime.

[blankedboy]

Keiichi's throat clawing from Higurashi episode 4. It made feel physicaly ill.

I dunno, the very end of Episode 8 where

Spoiler: This happened

Mion nails all of Keiichi's hands down

was alot more sickening than that. I swear, I was actually ready to feel the pain in my own fingers... that's a sign of an AWESOME anime.
xD

 

[Nexus4]

The whole 'End of Evangelion' alternate ending to Neon Genesis, seriously both of those episodes were extremely fucked up!

 

[blankedboy]

The nail-ripping scene from Higurashi No Naku Koro Ni

Spoiler

Fuuuucking hell.

Goddamnit, I hate that scene.
I'm halfway through watching Higurashi, and only just got up to that...

:S

 

[SilkySkyKitten]

I haven't seen things like Elfen Lied and such, but...

Spoiler

...Tetsuo's hallucinations and his eventual transformation in Akira were VERY unsettling.