DORUmon

DORUmon (ドルモン)
A Beast Digimon that is, because of the outdated Interface on its brow, presumed to be an experimental "Prototype Digimon" from before Digimon were discovered. The personality of natural Combat Species Digimon manifests particularly strongly within it, so its combat instinct is high; it often barks and bites at everything as a result, though it apparently feels a sense of attachment to something after biting it. The data that is said to have been hidden within the deepest parts of its Digicore during an experiment is the potent life-force data of the legendary beast, the "Dragon", and it is said to have the potential to grow into a mighty Digimon. Its Special Move is firing an iron sphere from its mouth (Metal Cannon). Signature Move: It is able to fire an iron sphere even while charging, although it's more powerful if it fires after standing still and accumulating power (Dash Metal).

Etymology
DORU: ドル Doru, an acronym for Digimon OR Unknown-Monsters.