The SpongeBob Movie: Sponge on the Run

In Bikini Bottom, Plankton hatches yet another scheme to steal the Krabby Patty secret formula, but Karen points out that SpongeBob has unwittingly foiled every one of his previous plans. Meanwhile, in the glitzy underwater metropolis of Atlantic City, the vain King Poseidon relies on snail slime to keep his appearance youthful and, running low, orders his servants to procure a new snail. Seizing on Karen's observation, Plankton kidnaps SpongeBob's beloved pet snail Gary and has him delivered to Poseidon, calculating that without Gary, SpongeBob will be too grief-stricken to interfere. SpongeBob and his best friend Patrick discover that Gary has been taken to Atlantic City. Plankton covertly provides them with Otto, a robot vehicle built by Sandy, secretly hoping the duo will never return. Back at the Krusty Krab, SpongeBob's absence sends the kitchen into chaos: angry customers riot, and Mr. Krabs and Squidward struggle to hold the restaurant together. On the road trip, SpongeBob and Patrick encounter Sage, a mystical tumbleweed spirit, who tells them they are on a destined mission and presents them with a Challenge Coin representing bravery. They face a series of surreal trials, including a battle against ghostly zombie pirates, ultimately defeating the evil spirit El Diablo. Arriving in Atlantic City, they learn Poseidon enslaves each snail he acquires until its slime runs dry, at which point the snail is discarded alongside the others. Dazzled by the city's distractions, SpongeBob and Patrick lose track of their mission, wake up inside Poseidon's palace, and are arrested while attempting to rescue Gary. Back in Bikini Bottom, a despondent Mr. Krabs, believing SpongeBob is gone forever, hands the secret formula over to Plankton. Plankton, however, finds the victory hollow and joyless without the rivalry that gave it meaning. Learning that SpongeBob and Patrick are sentenced to execution, a remorseful Plankton joins Mr. Krabs, Squidward, and Sandy on a rescue mission to Atlantic City. In the dungeon, SpongeBob and Patrick realize the Challenge Coin carried no magical power — their courage was always their own. Before the execution can proceed, their friends appear and each delivers heartfelt testimony about SpongeBob, drawing on memories from a shared childhood summer camp. Their words move the crowd, and SpongeBob and Patrick seize the moment to stage a musical performance that distracts Poseidon long enough for them to grab Gary and flee. Cornered during the escape, Poseidon offers to drop all charges if SpongeBob abandons Gary. SpongeBob refuses, explaining that his friends put their lives on the line to save him — he will not betray that loyalty. Confronted with SpongeBob's selflessness and his own profound loneliness, Poseidon has a change of heart. He accepts SpongeBob's offer of friendship, drops his vanity-driven cruelty, reveals his natural appearance, and frees every snail he had enslaved, sending them all home to Bikini Bottom.

Sources: Wikipedia