Special purpose sniper
From Halopedia, the Halo wiki
The Special Purpose Sniper is a deleted Covenant species seen in the Halo 2 Collector's Edition DVD. Its arms were used like a tripod (but not act like one), and that it could flip from side to side, without having to switch weapons. It would also be able to hang from trees and building struts. It could have been used instead of the Jackal Snipers in Halo 2.