Plankton

Sheldon J. Plankton is one of the main characters and is primarily the main antagonist of the series. He is voiced by Mr. Lawrence.

Early life
He was initially friends with Eugene H. Krabs. They have been friends with each other since they were babies. At school, they were social outcasts due to being nerds. They always stuck up for each other. Once at a fair, Mr. Krabs learned about money and it's value by finding a penny. He spent it on a balloon for Plankton. It sent him up into the sky.

Starting a business
After the closure of Stinky Burger, Mr. Krabs and Plankton started their own restaurant. They fed Old Man Jenkins a Plab Patty which fatigued him. They squabbled, with Mr. Krabs only giving Plankton part of the recipe. This event marked the end of their friendship. Since then, he has been arch-enemies with Mr. Krabs.

After the end of their friendship, Plankton started the Chum Bucket, a failing restaurant with next to no customers.

Personality
He is known as a mad scientist, using extremely expensive inventions. One of the only reasons that he invents things, is to steal the Krabby Patty Secret Formula, something that he'd do anything to get.