Drinniol, known to the UESC Marathon's crew as "Hulks," stand over ten feet tall. They have almost no fat on their entire bodies, which forces them to eat constantly. They are incredibly strong, and able to kill humans with one strike from their bare hands. Slow-moving, they are nevertheless deadly at close range due to their heavy crushing strikes.
The Drinniol appear only in two levels in Marathon, once in a level that has several BOBs in it, and another time in a remote quarantine storage.
The Hulk is an enormous and rather slow creature, but it is incredibly strong. The science report indicated that it had no body fat, and therefore had to be fed often to keep it active. One crew member reported seeing one of these creatures pointing to itself and mumbling "Drinniol" right before it "picked Johnny up by the shirt and crushed him against a pillar".
- Leela, from Marathon, Defend THIS!, Terminal 4
- The Drinniols inspired a cut enemy from Halo 2.
- Hunters from Halo, although named after a different Marathon enemy, essentially have the same gameplay purpose as Drinniols and Hunters from Marathon, not to mention being similar in appearance. Both are slow moving, large, incredibly durable enemies that are extremely lethal at close range, being able to kill the player in one or two hits. They are also usually in groups of two. However, Drinniols have no ranged attacks, weak points, and are slower.