Drinol

''
 * --Gamesradar article

The Drinol is a Covenant species that was cut from Halo 2.

In the Behind the Scenes featurette from the DVD included with the Halo 2 Collector's Edition, Drinol are described as huge beasts that are kept contained and segregated from the other forces. Possessing phenomenal strength, they are often used to smash enemy vehicles.

Marathon Connection
Bungie enjoys making references to their previous game franchise, Marathon, into the Halo series.

From a description of the Hulk in Marathon:

The term "Drinniol" is very similar to "Drinol," indicating a reference.