From Halopedia, the Halo wiki

A fan-made image of Mister Chief created for use in Template:Realworld.
This article contains information about a non-canonical subject that, while official, is not part of the established Halo universe.
A render of the Tankbeast.

The Tankbeast is a deleted Covenant species revealed by Bungie employee Paul Russel on Twitter.[1] The Tankbeast would have stood roughly 3.5 meters (11.4 Foot) tall, with no visibly-distinct head. The Tankbeast also had an underslung weapon, and with armored legs and body. It may have been an inspiration for the Lekgolo.