The Gúta

Load up the mission Nightfall and keep progressing, after the first 2 sections I think you will find 2 of these guys. Go kill them or let them kill the covenant for you but they will also want to kill you. To get rid of these giant behemoths just shoot them in the bloody head with your sniper or throw a sticky at them after that say good bye to them.

These beefy boi's are around 6 metres tall. They have long sharp claws, hella beefy bodies and a head with tusks. Go burn them with plasma and crap then run away.

Here is some lore about the Guta
The Guta are gigantic, semi bipedal type of species native to the world of reach.
Some belive that ONI created the Guta for a secret Campaign against the Covenant.
They can be recognised by their gigantic size, long claws and tusks.
These fat asses are extremely aggresive towards humans, creatures like the Moa and more. Although the Guta is still very dangerous it can still be taken care of by some humans such as the spartans.