One of the funniest pranks my college dorm's freshmen floor did (in the 60s) was to manufacture fake poop from chocolate cookies and tempera paint, and strategically "decorate" the shared bathroom with it. Then lurk in wait for the reactions. Hilarious! (Guess you had to be there.) Times were a lot more innocent.
A fellow dorm-mate would secretly chew up some Payday candy bar, then ‘puke’ it out on a fairly clean floor.
Then ... as those around him watched, lick it back up.
I had forgotten about that.