20,000 Digi-Leagues Under the Sea - S2.E16

MegaSeadramon traps the DigiDestined under an oil platform, and Cody is forced to find Joe, lying in the process. When they return, the DigiDestined find the Digi-egg of Reliability, which Cody is reluctant to accept due to lying. However, Joe convinces him to overcome his self-doubt and Cody allows Armadillomon to Armor Digivolve into Submarimon, freeing MegaSeadramon.