Prisoners

The prisoners are characters who make a few background appearances in the series. They are usually tough and muscular. They appear in the episodes "The Inmates of Summer," "Krabby Road," "Back to the Past," "Karate Star," "The Executive Treatment," "Teacher's Pests," and "The Krusty Slammer."

The prisoners

 * A purple thug
 * A whale
 * A blue thug
 * Green-tattooed thug
 * Sailor thug
 * Green construction worker
 * Fred
 * Incidental 64
 * Incidental 106
 * Incidental 68
 * Incidental 6
 * Incidental 155

"The Inmates of Summer"
The prisoners first appear boarding the Inferno Island boat. tries to amuse them but fails to do so. They then arrive at Inferno Island, where they do very dull activities that SpongeBob and think are fun. Afterward, they decide to set up a play with SpongeBob and Patrick but they use it to sneak out of the island.

"Karate Star"
The prisoners appear when Patrick karate chops a police truck and lets them free.