SpongeBob trusts Squidward to take good care of Gary while he goes to a jelly-fishing convention. However, Squidward neglects him and Gary falls sick. SpongeBob calls the veterinarian, who gives him a syringe filled with snail plasma. Squidward accidentally injects the serum into SpongeBob’s nose, causing SpongeBob to turn into a snail. The transformed SpongeBob approaches Squidward, who runs in fear, accidentally injects himself with the serum, and thus turns into a snail himself. The three snails are last seen meowing a song on a fence at night, which annoys Patrick.