The monster(s) that you don't want to meet in real life..

[JohnL]

The Blob
The parasites in Night of the Creeps
The bugs in They Nest (ok, not really a monster, but the idea of bugs laying eggs inside you is really creepy)

[jmc]

Of the Universal monsters, the Wolf Man would be the one I'd least want to run into.    

Wouldn't want to run into any of the others monsters....zombies would probably be one of the worst, especially if they were fast moving.  Also agree on any form of the Alien.

[BGrade]

Ok this is going to sound stupid.
However, I think the big ass rabbits from night of the lepus.

Big rabbit with blood on it's mouth.  I think I would freeze solid and pee because it is so real.

Anyother monster would be both scary and interested before it killed you.

Werewolf works on the same theory.  It is seems so real that you instantly know you are screwed.

[gecko brothers]

What about ash's hand

[Dunners]

Michelle "butch' Rodrigez

[Ellie]

A killer Tomatoe! No..just kidding..I could not resist.