Build a trap out of metal pillars about 5x5x3 (5 pillars wide, 5 pillars long and 3 pillars tall) with a ramp on one end and bring a platform saddled Paracer with a cannon ontop to fire from outside the trap. Simply lure the Elemental in and line up your Paracer so the turret is aiming at the Elemental’s head. Pump HP into Paracer incase the Elemental decides to chuck boulders at it, cannon might get a little damaged but not by much.