In the Jellyfish Caves, there is a sock on a ledge behind a gate. The gate can be opened by Patrick by throwing a melon onto the pressure plate.
SpongeBob is able to clip out of the cave using a geode. He can jump around the gate, activate a checkpoint, and deathwarp to respawn on the other side of the gate. It is also possible to skip the deathwarp and ledge grab back into the map.