Armored Monstrosity

Armor Magnet. All players within 35 feet wearing armor with steel on it or bearing steel weapons are to make a DC 18 Strength saving throw, or their weapons and armor will be absorbed into the creature. They can make a DC 17 Strength check to fetch their weapon out of the monstrosity during their next turn. (If using this ability, CR immediately increases to 4).

Whirlwind of Steel. The construct of armor makes three melee attacks. The Armored Monstrosity is stunned for one turn after using this ability.

Longsword. Melee Weapon Attack: +5 to hit, each 5 ft., one target. Hit: 10 (2d8 + 2) slashing damage.

Shield Bash. Melee Weapon Attack: +4 to hit, each 5 ft., one target. Hit: 8 (2d8) bludgeoning damage. The player must roll a DC 16 dexterity saving throw or be afflicted with stunned.

Ghostly Howl. All players within 15 feet are to make a DC 16 Wisdom saving throw, or take 6 (3d4) psychic damage.

Steel Coffin. One chosen player must make a DC 22 dexterity saving throw, or the Poltergeist spirit will encase the player in armor, dealing 10 (1d12+4) psychic damage. The player is restrained in place until they roll an 20 for dexterity to break out of the armor's control, dealing it 2 (1d4) damage. All damage dealt goes directly to the Armored Monstrosity. The Armored Monstrosity can still attack in this phase, but cannot move. This can be used once per battle.