Animated Invulnerable Coat of Arnd

Antimagic Susceptibility. The armor is incapacitated while in the area of an antimagic field. If targeted by dispel magic, the armor must succeed on a Constitution saving throw against the caster's spell save DC or fall unconscious for 1 minute.

False Appearance. While the coat remains motionless, it is indistinguishable from a normal suit of chain mail.

Invulnerability. The coat is immune to critical hits and sneak attacks and takes ten points of damage off every hit and twenty points off acid, cold, electricity, fire, and sonic damage.

Multiattack. The armor makes two melee attacks.

Slam. Melee Weapon Attack: +8 to hit, reach 5 ft., one target. Hit: 9 (1d6 + 6) bludgeoning damage.

Legendary Reaction (3/Day). When the coat is dealt with more than 5 damage it chooses this reaction if available. The coat is pushed back 5 feet and falls to the ground as if defeated and stays prone on the ground until a creature(s) is within 5 feet on it. Then it attempts to sweep the creature(s) from its feet. The coat makes a Strength Check and the target creature(s) make a Dexterity Check. If the coat's Check was higher then the creature is prone and takes 1d6 bludgeoning damage, if the coat rolled a 20 before the modifier then the creature takes 2d6 bludgeoning damage instead. If the creature's Check was higher then it dodges the reaction by jumping. If the creature rolled a 20 before the modifier then it jumps and lands on the coat restaining and keeping it prone until the coat makes a DC Strength saving throw based on the creature(s) size(s). For each creature on top, it must succeed each individual DC Strength saving throw for each individual creature on top of it., Tiny DC 2, Small DC 5, Medium DC 10, Large DC 15, Huge DC 20, Gargantuan DC 30.

Legendary Strangle (1/Day).  Once the coat is below half of its starting health, the coat covers and strangles a target creature within 5 feet. The target creature must make a DC Dexterity 14. If it is a success the coat attempts until a target creature fails. On a fail , the target creature becomes restrained and gains +5 AC and the coat's Invulnerability.  At the beginning of the creature's turn, the creature attempts a DC Strength Saving Throw 18, on a fail, it takes 2d8 strangling damage and is restrained and cannot take actions or bonus actions. On a success it takes half that damage instead and is restrained and can not take actions or bonus actions. This is continued until the target is dead or is taken off by other creatures. To take off the cloak, at least three other creature must make at DC Strength Saving Throw 18. On a fail the restrained creature takes 1d6 strangling damage. On a success the unrestrained creatures each deal 1d6 bludgeoning damage that is not prevented or resisted by this creature's traits, and the target creature is unrestrained, and the coat is stunned until the end of its next turn.