Druddigon is a large, blue, draconic Pokémon with medium-sized wings shaped like thistle leaves, although it is rarely seen flying. Its bright red head is harder than rock and is very rough. It has a set of glaring, ferocious pale yellow irises. Its arms are longer than its legs, giving it the appearance of a hunchback. It has a thick, moderately-sized tail and sharp white claws on both the hands and feet. It also has tall, conical, red spikes: three on each arm, one on each shoulder, two on each leg, and four on its tail. It has a blunt, brutal snout, bearing a maw with no discernible teeth; instead, small fang-like protrusions sprout from its jaws. It has a series of olive, ellipsoid scutes running across its belly.
Druddigon is known to be vicious and cunning. It warms its body by taking in sunlight with its wings; if its body temperature lowers, it becomes immobile. It has savage physical strength; it nimbly chases prey around its den, using its outstretched claws to catch them, or charging into them face-first. Instead of making its own nest, it lives in caves and tunnels dug out by other Pokémon, such as Diglett, Dugtrio, Onix, and Excadrill.
Druddigon appears to be based on the red-headed rock agama. Its natural appearance and cave-dwelling behavior also seem to resemble a European dragon. Druddigon's grotesque appearance and ability to become immobile when cold is reminiscent of gargoyles and trolls, both of which turn to stone under certain conditions.
Druddigon may be a combination of dragon, ruddy (reddish in color), and possibly dread.
Crimgan may be a combination of crimson and 顔 gan (face) or 岩 gan (rock).