I think it would be a real cool new exotic that is a heavy weapon that goes in the primary slot. But have it be like some sort of rocket launcher that does not discharge rounds out of it but shoots out a sort of battering ram that retracts back into the tube, a sort of hammer insta-kill melee. The perks on it would be like gain a overshield when clip is fully loaded. Like the one you gain from flame shield, or force barrier. The second perk would be when you press the left trigger instead of zooming in it cause you to dash forward.