Part one episode 38 for the first time.

The second time was in Episode 46 of Part II.

Rolling beast, [コロモンン/Koromon] is a cross-platform product developed by Bandai Company in Japan. As an electronic pet, it is a fictional creature appearing in digital Tyrannosaurus, and it is the embryonic form of Yagami Taichi's digital baby Yagu. The tumbling beast, named for its bony tumbling, takes foam as its attack mode. Bite your head to show your closeness to others.

Battle Tyrannosaurus Rex, a fictional creature in the cross-platform product Digital Beast series developed by Bandai Corporation of Japan, centered on electronic game consoles, first appeared in Digital Beast Adventure, and then appeared in Digital Beast Adventure II, Digital Beast Battle and Digital Beast Adventure III, and was the partner of Taiyi.