Astral Ravager

Adaptive Resistance. The Astral Ravager gains resistance to any damage type it receives until the end of its next turn. After receiving the same type of damage three times, it becomes immune to that type for the remainder of the encounter.

Rampant Assault. The Astral Ravager channels its ferocious energy into each attack. When it hits with a melee attack, it can choose to take a -2 penalty to its AC until its next turn to deal an extra 8 damage to the target.

Multiattack. The Astral Ravager makes two attacks: one with its slam and one with its bite.

Slam. Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit: 13 (2d8 + 4) bludgeoning damage.

Bite. Melee Weapon Attack: +6 to hit, reach 5 ft., one creature. Hit: 10 (1d12 + 4) piercing damage.

Consume Essence (Recharge 5–6). The Astral Ravager targets one creature it can see within 60 feet. The target must make a DC 15 Wisdom saving throw, taking 4d6 psychic damage and 4d6 necrotic damage on a failed save, or half as much damage on a successful one. The Ravager regains hit points equal to the necrotic damage dealt.