Animated Armor

A friendly animated armor is a wizard's housekeeper or a dwarven smith's automated apprentice. The framing is custodial. Someone with the Animate Objects spell or the right ritual binding put a guardian spirit into a suit of plate, gave it a one-line standing order ("guard the door", "follow the master"), and it has been doing that for years. If the party inherits it, they inherit the standing order with it. They can't change the order in the field. The suit obeys whoever spoke the binding word, and that person isn't them.

In combat, point it at the loudest threat and let it walk over there. It can't coordinate, can't call out flanking, can't even hear a warning shouted in Common. Two Slam attacks per round at +4 for 5 damage is real chip damage at low levels, and AC 18 with 33 HP means it absorbs hits a PC can't afford to take. Stick it in the front line, on the doorway, on the stairs, anywhere a body in plate buys the casters two rounds. It will not retreat. It will not pursue once the threat is gone. It returns to its post.

The texture comes from the limits. The party tries to ask it questions. It does not respond. They try to take it apart for the breastplate. It defends itself. Someone tries to ride it. Hilarious for one round, then it stops and stands still with the rider on top. Make sure the suit's owner is a real NPC the party has reason to respect, because that NPC is the only one who can rewrite the order.

When the binding word is finally spoken and the armor goes inert, let it land with a clatter. The construct should feel like furniture again the moment its job ends.

Animated armor is a haunted-house jump scare with a CR rating. The trick is that it doesn't telegraph. The party walks into a vaulted hall lined with suits of plate, looks for the obvious threat, and one of those suits steps off its stand on initiative. AC 18 means low-level martials will miss often, and 33 HP plus immunity to Poison and Psychic means it survives the first round of panic damage from a CR 1-appropriate party.

Open with the suit already in motion when the party is past it. Blindsight 60 ft. and Passive Perception 6 mean it doesn't see them coming, it senses them when they're close, and once they cross that threshold it commits. Multiattack gives two Slam attacks at +4 for 5 damage each, which is enough to drop a wizard in two solid hits. Walk speed is only 25 ft., so the smart play is to stick to a single target rather than chase. Pick the squishiest visible PC and stand on top of them.

The condition immunity list is the real puzzle. Charmed, Frightened, Paralyzed, Petrified, Poisoned, none of it works. A party leaning on Hold Person or Tasha's Hideous Laughter will burn slots for nothing and start to feel the encounter pivot under them. It also has Intelligence 1 and no language, so it can't be reasoned with, surrendered to, or tricked. It just keeps swinging until something stops moving. Fire is a clean answer if anyone has it; otherwise it's a slugging match.

Run two or three at once if you want a real fight. A single suit dies in a round or two against a CR 1 party, but a pair flanking a corridor turns the corridor into a problem. Keep the rest of the suits inert and make the players guess which ones are next.