Amoebas are microscopic one-celled organisms that first appear in the episode "Patty Hype."
Role in series
When Mr. Krabs is not receiving business at the Krusty Krab in "Patty Hype," he watches a show about them in his office.
They also appear when SpongeBob turns Plankton into a baby in the episode "Goo Goo Gas." He is shrunken down after being hit by the baby gas to microscopic smallness. The Amoebas are shown to say that Plankton's baby size is microscopic.