Tetomatli

Diving Head Slam. If the tetomatli is flying and moves at least 20 feet straight toward a target and then hits it with a head slam attack on the same turn, the tetomatli can use Tremor as a bonus action, if it is available.

Heavy Flier. The tetomatli can fly up to 30 feet each round, but it must start and end its movement on a solid surface such as a roof or the ground. If it is flying at the end of its turn, it falls to the ground and takes falling damage.

Magic Resistance. The tetomatli has advantage on saving throws against spells and other magical effects.

Magic Weapons. The tetomatli's weapon attacks are magical.

Siege Monster. The tetomatli deals double damage to objects and structures.

Multiattack. The tetomatli makes one head slam attack and one wing buffet attack.

Head Slam. Melee Weapon Attack: +8 to hit, reach 5 ft., one target. Hit: 21 (3d10 + 5) bludgeoning damage. If the tetomatli scores a critical hit against a target wearing metal armor, the target must succeed on a DC 15 Strength saving throw or its armor is destroyed. A creature wearing magical armor has advantage on this saving throw. A creature wearing adamantine armor is unaffected.

Wing Buffet. Melee Weapon Attack: +8 to hit, reach 5 ft., one target. Hit: 12 (2d6 + 5) bludgeoning damage.

Tremor (Recharge 6). The tetomatli slams its head repeatedly into the ground, creating a magical shockwave. Each creature within 20 feet of the tetomatli must succeed on a DC 15 Dexterity saving throw or be knocked prone and have disadvantage on attack rolls and Dexterity checks until the end of its next turn.