Grimrock

I was glad to dig up a hidden treasure chest in the swamplands. It even granted me a steam achievement, since it was my third uncovered treasure. After unlocking it with a lockpick, I clicked to open...

... and nearly shat my pants as the posing bastard displayed a large array of sharp teeth and slimey tongue and tried to eat me back! Hahaha! Did not see it coming! xD

See for yourself...(I loaded an old save for the recording)

Scared the shit out of me too

Yup. Wasn't on that chest, but I did jump and freak out on my first ever Mimic, which was also a locked chest.

I think it's quite random. I have found two of those nasties.

On my second run, those things have not appeared on the same location. Those buggers are friggin random! D=

Is there a visual cue? Maybe it's my mind playing tricks on me but the lock looks like a tongue sometimes...

Even after seeing a few, you still forget and get a nasty surprise =D

I wonder if you can preeminently attack them.