Please don't list this on a work's page as a trope. Examples can go on the work's YMMV tab.
Nightmare Fuel: Deep Blue Sea
Most of the shark kills, but one in particular: half of a guy is eaten... and then the foot twitches.
How about the lead scientist who was strapped to the gurney and used as a Battering Ram to break the observation window? Made ten times worse by the fact that that he was not only still alive because of his oxygen mask, but awake. *shudders*