Jeff Grossman wrote:A good one is just to dress like a zombie and gnaw it right out of the mold.
Best gross-out prank I ever heard of was perpetrated by a classmate of my brother's in medical school. This classmate liked to eat, of all things, raw liver.
The med students were doing cadaver dissection. It was the middle of July and the dissection lab was in an old building that didn't have air conditioning, so conditions were pretty bad already. The classmate smuggled a bag full of raw liver into the lab and hid it in the thorax of his cadaver. Midway through the lab the threw down his scalpel and yelled, "I can't stand it! I'm just SO HUNGRY!!". He then reached into the cadaver, pulled out a handful of raw liver, and started eating it with gusto. Several students fainted and several lunches were lost.
-Paul W.