Monochromon

In Digimon Adventures 01, the 3rd digimon the DigiDestined encountered were, 2 Monochromon.

Appearence
Monochromon are giant Digimon, that's half-rhino half-dinosaur, with rock-like armor.

Digimon Adventures 01
In the third episode the DigiDestined saw two Monochromon that surrounded them and the two Monochromon fought until they fell into the ocean. Another Monochromon pulled Etemon's transport while a bunch of them were seen outside of Datamon's Pyramid who got sucked into the vortex of Etemon's Dark Network with the Tyrannomon and Gazimon thanks to Datamon shooting his attack into it.

Digimon Adventures 02
A Monochromon was the first Digimon encountered that was under the control of one of the Digimon Emperor's Dark Rings. He attacked the DigiDestined when they found the Digi-Egg of Courage and chased after them when they fled. He then engaged Flamedramon in a fight and was freed from the Dark Ring by his "Fire Rockets".

Eventually another DigiDestined by the name of Rosa has a Gotsumon, that Digivolved into a Monchromon.

Attacks

 * Volcanic Strike
 * Slamming Attack