It is not known to evolve into or from any other Pokémon.
Druddigon is a large, blue, draconic Pokémon with medium-sized wings shaped like thistle leaves. 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 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 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. It infiltrates the tunnels of other Pokémon, such as Diglett and Dugtrio, and waits for its prey to pass by. Druddigon lives in caves, and is carnivorous.
Druddigon shares its category with Gabite. They are both known as the Cave Pokémon.
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 and ruddy (reddish in color). The name also appears to show Welsh influences. These include the dd, a common digraph in the Welsh language, and the ending -igon being comparable to Welsh -igion. Wales has also had a long association with dragons, with one being featured on its flag. "Drudd" may also be a corruption of "dread", due to Druddigon's fearsome appearance and strength.
Crimgan may be a combination of crimson and 顔 gan (face) or 岩 gan (rock).