Warforged Landtank

Charge. If the sentinel moves at least 20 feet straight toward a target and then hits it with a ram attack on the same turn, the target takes an extra 10 (3d6) bludgeoning damage. If the target is a creature, it must succeed on a DC 15 Strength saving throw or be knocked prone.

Spell Turning. The sentinel has advantage on saving throws against any spell that targets only the sentinel (not an area). If the sentinel’s saving throw succeeds and the spell is of 1st level or lower, the spell has no effect on the sentinel and instead targets the caster.

Multiattack. The sentinel makes two ram attacks.

Ram. Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 13 (2d8 + 4) bludgeoning damage.

Poison Vent (Recharge 5–6). The sentinel exhales poison in a 15-foot area. Each creature in that area must make a DC 15 Constitution saving throw, taking 27 (6d8) poison damage on a failed save, or half as much damage on a successful one.