MegaSeadramon appeared under the control of one of the Digimon Emperor's Dark Spirals, trapping the DigiDestined on an offshore oil platform. Cody escaped in a submersible to contact Joe, who arrived with Ikkakumon and Whamon. Ikkakumon held off MegaSeadramon while Joe and Whamon freed the DigiDestined, and then Cody retrieved and activated the Digi-Egg of Reliability, digivolving Armadillomon to Submarimon. Ikkakumon and Submarimon then destroyed the Dark Spiral controlling MegaSeadramon.
During BlackWarGreymon's assault on the Destiny Stones, the DigiDestined contact Ikkakumon for help protecting the sixth stone. Ikkakumon arrived with MegaSeadramon and a pod of Dolphmon, but they were unable to stop BlackWarGreymon from destroying the stone.

Related anime:

Digimon: Digital Monsters Season 2 TV, 2000

Voice actors:

Steven Blum, English