I had this idea for a UNSC-modified Hunter mech on my way home from class.

History:
The UNSC has a nasty habit of improving on any bits of Covenant technology they capture and this Hunter-class assault mech is no different.

Though heavily damaged in battle, this Hunter was intact enough for the UNSC to repair for use by the elite Spartan Squadron. The Fuel Rod Gun was disassembled and sent off to a Think Tank for reverse-engineering; in its place is a Spartan Laser, which has a third of the charge time and unlimited shots due to the Hunter's superior power source. While standard Hunters would use their cannons as clubs, the UNSC's Hunter has had a prototype Plasma Axe blade mounted to the bottom of its gun to reduce possible damage to it. Also new are the improved shields on its left forearm that are lighter and can cut through enemy hulls easier. It also has limited flight ability due the jet engines that replaced the old spikes. Finally, its legs have been almost completely rebuilt with stronger armor but less mobility, a worthy trade-off considering its new defenses.

It also has various cosmetic changes to make it blend in with the rest of the Spartan Squadron's mecha.

EDIT 3: I'm tired of answering this in comments: this UNSC Hunter is a robot. The wormy part was replaced with AI containment material from Mjolnir armor.

EDIT: Changed the gun a little. I took off that machinegun and added a scope and a nifty axe blade.

EDIT 2: Found better GP-02A lineart for the legs. Now the UNSC Hunter stands a little prouder and taller.