From Doom Wiki
A Green Chaos Serpent in Hexen.
The Green Chaos Serpent is an enemy from Hexen, and also D'Sparil's steed in Heretic. They appear as tall serpentine humanoids with large horned heads. They spit out fireballs which cause a lot of damage, especially on the highest difficulty setting. Their melee bite attack is not as damaging, since it takes roughly a second or so for a bite to damage the player. It is inadvisable for a player to attack close-up unless the player is playing as the Fighter class or has no other means to attack it. Green Chaos Serpents in Hexen have 250 Hit Points, while the one D'Sparil rides in Heretic is much stronger at around 2000 Hit Points. They first appear in Hexen in the first hub.
