Basically take the attack animations for the Sentinel shield and put them on a legendary (or exotic) shield in the heavy slot. I’d imagine the damage wouldn’t be too great, but it would have absolutely insane defense when guarding. Guarding and attacking both use heavy ammo like swords.
Just a weird idea I thought of. Feel free to leave your thoughts below.
Edit: FYI this is just a concept, not a confirmed new weapon type by Bungie or anything like that.