I think that is the fun song episode, so the title is "F.U.N.". Reasons being that spongebob just got the krabby patty back from plankton, and everyone is cheering for him (for he's a jolly good rookie...). They also put a large donut around him as they throw him up into the air. While in the air he thinks about plankton and how he must be lonely with no friends. So to help him, he goes to the chum bucket and asks him to go jelly fishing.