Black Knight

Antimagic Susceptibility. The Knight 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 Knight remains motionless, it is indistinguishable from a normal suit of armor.

Multiattack. The knight makes two melee attacks with its dagger, or an attack with its pike and dagger.

Pike. +4 To hit, 5 (1d10) Piercing damage. 10 ft. range

Dagger. +4 to hit, 2 (1d4) Piercing damage. 5 ft range

Lockdown. The armor can split itself into multiple pieces and surround one medium or Small creature it can see within a 5 ft range, The creature needs to succeed a DC 11 Strength saving throw or be Grappled by the armor.  this gives the creature full cover against attacks. Every turn the creature starts inside the armor, it takes 1 (1d4-1) Necrotic Damage. The creature cannot take reactions, and needs to use its action to pass a DC 13 Strength Saving throw, upon a success, The target escapes the armor.