Probably Pupa, but not really a scary one, more like disgusting.
The only thing scary about Pupa is it's quality.
Well, as I said "not really a scary one", but for some people it could be. That's why I posted it here.
For me it wasn't scary at all, only disgusting since the sound effects were too "real".
Agreed. Watching Pupa is uncomfortable to the point of it being scary,
As for scary manga, I finished reading Gyo and Uzumaki by Junji Ito. His stories are very creepy and unsettling, but instead of using the same old themes (ghosts, murderers,...) he focuses on random things like fish and spirals and it works. Would recommend to any Lovecraft fans.