SpongeBob SquarePants Season 5 Episode 1 Friend or Foe Episode Title:Friend or Foe.Episode Description:Mr. Krabs and Plankton have been rivals for a long time. However, one day, Mr. Krabs reveals to SpongeBob that they were actually best friends during their childhood. Through a series of flashbacks, Mr. Krabs tells the story of how that friendship deteriorated, the cause of their rivalry, how Mr. Krabs became obsesive with money, how Plankton became evil, and how the Krabby Patty sandwich was created in the process.