Auran Dreadnoughtus

Unshakable. On the ground, the dreadnoughtus has advantage on all checks against actions that could knock it prone.

Living Meteor. If killed mid-flight, the dreadnoughtus will enter a plummeting state, barreling down at a speed of 60 feet. On impact, the Crash reaction triggers.

Multiattack. The dreadnoughtus slams twice at once. If both land on the same target, secondary effects will not apply.

Slam. Melee Weapon Attack: +8 to hit, reach 10 ft, one target. Hit: 70 (8d20) bludgeoning damage. Targets at or below Large size must make a Constitution (DC 16) saving throw or be knocked prone, thrown up to 20 feet backwards and take 10 (1d20) extra bludgeoning damage.

Rear. The dreadnoughtus makes an intimidation check and immediately multiattacks afterward. This action can only be done while grounded.

Crash. Ranged Weapon Attack: +8 to hit, radius 120 ft, multiple targets. Hit: 90 (6d20) thunder damage. The damage type becomes bludgeoning for creatures hit point-blank rather than by the ensuing shockwave.