Planeshift Tarkir
Immutable Form. The custodian is immune to any spell or effect that would alter its form. Magic Resistance. The custodian has advantage on saving throws against spells and other magical effects. Magic Weapons. The custodian's weapon attacks are magical.
Multiattack. The custodian makes two slam attacks. Slam. Melee Weapon Attack: +10 to hit, reach 5 ft., one target. Hit: 19 (3d8 + 6) bludgeoning damage. Slow (Recharge 5–6). The custodian targets one or more creatures it can see within 10 feet of it. Each target must make a DC 17 Wisdom saving throw against this magic. On a failed save, a target can't use reactions, its speed is halved, and it can't make more than one attack on its turn. In addition, the target can take either an action or a bonus action on its turn, not both. These effects last for 1 minute. A target can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.
Defender. The custodian adds 3 to its AC against one melee attack that would hit it. To do so, the custodian must see the attacker.