Bullet Vrock

Magic Resistance. The vrock has advantage on saving throws against spells and other magical effects.

Battle Fervor. Once engaged in combat, bullet vrock will fight unto death or victory. The bullet vrock deals an additional 1 damage and gains an additional + 1 to hit on melee attacks for every 10 hit points the bullet vrock is missing. This additional damage is applied to any damage directly dealt by the bullet vrock.

Stinger Strafe. Bullet vrock shoots its expendable stingers in a 40-foot line that is 10 ft. wide. Each creature in that line must succeed on a DC 14 Dexterity saving throw, taking 12 (6d4) piercing damage on a failed saving throw, or half as much on a success. 

Fell Stinger. Melee Weapon Attack: +6, reach 5ft., one target. Hit: 38 (7d10 + 3) piercing damage and 15 (3d10) poison damage. If this attack hits, bullet vrock's hit points become 0 and it dies. If Fell Stinger reduces the target to 0 hp, the target immediately dies.

Spores (Recharge 6). A 15­-foot­-radius cloud of toxic spores extends out from the vrock. The spores spread around corners. Each creature in that area must succeed on a DC 14 Constitution saving throw or become poisoned. While poisoned in this way, a target takes 5 (1d10) poison damage at the start of each of its turns. A target can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success. Emptying a vial of holy water on the target also ends the effect on it.