— Frank, "Pranks a Lot"
Real vomit is a gross-out novelty item seen in the episode "Pranks a Lot."
It is real emesis that contains green gastric content.
Role in the episode
When SpongeBob and Patrick are at the Palace of Pranks, trying to find the best novelty item in stock, they talk to the store owner, Frank, suggest numerous gags for them to buy. After SpongeBob shows disinterest in fake vomit, Frank jokingly suggests real vomit, to which SpongeBob responds "ew" and asks if he has anything decent. As a result, Frank suggests Invisible Spray, which they actually find interesting and end up buying.