Marchog

Marchog the Dragon Rider is a male acromantula.

Description
Described as "black" and "of average size", Marchog is one of the children of Aragog and Mosag, and thus a member of the Acromantula Colony of the Forbidden Forest.

Biography
At some point in late 1991 or early 1992, Rubeus Hagrid accidentally let loose a young dragon into the Forbidden Forest. The creature was found by an Acromantula who brought it back to Queen Mosag. Mosag immediately formed plans to use the beast as a weapon against the Centaur Herd. She chose her son Marchog to raise the creature, tame it, and, when it grew large enough, to ride it.

On Spider Day, Marchog, fastened to the dragon with a saddle of webbing, soared into the air and attacked the Centaurs, chasing them all the way to Hogwarts. In the chaos of the resulting battle, Marchog was attacked by the Metal Monkey (and presumably unsaddled) and his mount was killed. Marchog apparently survived, presumably escaping into the Forbidden Forest along with the other Acromantulas.