Koromon

Koromon (コロモン) is the first digimon Yagami Taichi and Yagami Hikari met.

Appearance
When he was born as Botamon, he is 30 cm high and looks like a botamochi-shaped creature with black fur, yellow eyes, and small ears. After evolving, Koromon looks like a pink, ball-shaped Digimon with floppy ears, bright-red eyes and sharp teeth.

As an Agumon he becomes a big Tyrannosaurus rex-like Digimon standing about 2 meters tall, and has yellow skin and light green eyes. He also has flattened forearms with broad, three-clawed hands, and distinct pectoral muscles. His legs and arms are shown to be very vascular. His tail is stubby, his head and snout are almost as large as the rest of its body, and his ears are very small.

As Greymon, he grows to be 8 meters tall. He is shaped as a bipedal reptilian Digimon whose design carries elements of the Ceratosaurus and the classic monster Gomora. He has orange scales with blue stripes covering his body. he has three clawed fingers on his hands and three clawed toes on his feet, with claws protruding from his heels. He wears a rhinoceros beetle-like skull on his head.

Digimon Adventure (movie)
Koromon first hatches from its egg as a Botamon and immediately latches onto Taichi's face. Taichi throws him off, and he runs under the nearby bed. After Taichi throws his googles at him, he retaliates by blowing bubbles at him. He eventually becomes trusting in Hikari who whistles at him and feeds him chocolate, causing him to evolve into Koromon.

When Hikari steals their cat's, Miko, foos and gives it to Koromon, he thanks her by latching onto her face as well and then Taichi's. Miko soon finds Koromon with its food, however, and attacks him. Taichi tries to protect him but Miko scratches them both, taking his food back. Koromon later introduces himself to Hikari and talks with her. He tells Taichi and Hikari that he is a Digimon from the Digital World.

At night, Koromon suddenly evolves into a big Agumon and begins roaming the streets, causing destruction on a small scale, while carrying Hikari on his back. He keeps roaming around the city causing trouble, but before he manages to cause any real casualties, a Parrotmon appears out of a huge egg in the sky. Koromon (Agumon) lashes out as Taichi arrives, which only angers the bird, causing it to destroy an overhead bridge and covering him and the two kids in rubble.

Out of the rubble, a Greymon appears in the Agumon's place and begins fighting back against Parrotmon. After a few minutes, the Greymon is knocked out, and only awakens when Taichi blows Hikari's whistle as loud as he can. He then lets out a blinding attack, and the two Digimon vanish.

Trivia

 * Koromon's name comes from the Japanese onomatopoeic word ころころ (Korokoro), used for something round and rolling.