The Arrival of Skullgreymon

The Arrival of SkullGreymon is the sixteenth episode of both Digimon Adventure and the Digimon anime series.

Summary
After receiving his crest, Tai begins acting strangely. He begins force-feeding Agumon massive amounts of food in order to make him digivolve further, much to Agumon's complaining. Joe's tag then leads everyone to a nearby coliseum-style football (soccer) stadium. Just when everybody (except Tai) begins to relax, Etemon attacks with a Greymon, and everybody except Agumon becomes trapped, forcing Agumon to digivolve. But, in his current state, Agumon (now Greymon) is easily beaten up by the other Greymon. Meanwhile, Joe finds the Crest of Reliability in the ground, which opens a hole in the floor, allowing the group to escape their prison. Almost as soon as he is out, Tai tries forcing (his) Greymon to digivolve by placing himself in danger. Greymon does digivolve, but into a corrupted digivolution known as SkullGreymon. SkullGreymon has no trouble defeating the other Greymon, and begins attacking the others. After defeating them in their digivolved forms, he runs out of energy, and goes back to being a Koromon. Tai realises his mistake in forcing him to digivolve further, and the group continue their journey.