Digimon Fusion Season 2 Episode 17

Resembles? Not at all? The Masquerading Phantom Thief Betsumon

Betsumon is a thief who uses cosplay costumes to resemble other Digimon, making him wanted in the Digital World regardless of his appearance. Wanting to capture Betsumon, Tagiru joins up with the Digimon Hunters who also have business with Betsumon. However, it turns out that Betsumon is an old friend of Gumdramon's though the Digimon does not remember him and goes on the offensive.