First seen in episode 3, the creature resembles a jet black, stallion but with a fiery mane, tail and fetlocks. There are wounds along its flanks and it is wreathed in dark, rising smoke. A horn protrudes from its forehead as would befit a Unicorn, however the wounds come from the removal of the most remarkable feature of a Pegasus - wings. It seems that the creature was put together rather than born. The Nightmare Pegacorn - the evil version of an already extremely rare creature.
It had a hold of sorts over a herd of five Pegasi. The Nightmare, as it came to be known, was finally killed when encountering and attacking the party, in episode 3.
The creature enjoys fire damage added to its melee attacks.