Mjolnir Powered Assault Armor/Mongoose

Were you looking for the vehicle, the M274 'Mongoose'?

MJOLNIR Powered Assault Armor/Mongoose is an experimental variant of MJOLNIR Powered Assault Armor featured in Halo Online. It is currently undergoing testing by SPARTAN-IVs on Anvil station.

Trivia

 * It is probably named for the vehicle of the same name.