The Dark Network of Etemon

The Dark Network of Etemon is the fifteenth episode of both Digimon Adventure and the Digimon anime series.

Summary
The group arrives at Server, and their first stop on the continent is at a village inhabited by Pagumon, where T.K.'s Digimon Poyomon becomes Tokomon. However, when Tokomon goes missing, Agumon becomes unsure of whether to trust the Pagumon after smelling some Koromon nearby. He finds them behind a waterfall, but is also found by some evil Gazimon who work for Etemon, the self-proclaimed ruler of the region. Agumon manages to signal the rest of the group, and with Tai, he digivolves and scares the Gazimon away. But then, Etemon summons his dark network (a network of wires in the ground), which de-digivolves Greymon and chases the group into a cave behind the waterfall. Luckily, this is where Tai's Crest of Courage is hidden, and after removing it, an alternative exit is revealed.