Weezing

Gas Cloak. Weezng is surrounded by a cloud of gas, any enemy that comes closer than 10ft from Weezing takes 7 (2d6) poison damage.  Weezing gains partial cover.  A wind of moderate or greater speed (at least 10 miles per hour) can disperse it, but the Gas Cloak will be formed again at the end of Weezing's next turn.

Explosive Death. Weezing explodes when it drops to 0 hit points.  Each creature within 20 feet of it must make a DC16 Constitution saving throw, taking 36 (8d8) acid damage on a failed save or half as much on a success.  A toxic cloud will form in that area, dealing 14 (4d6) poison damage to any creature that enters or starts its turn within that area.  The cloud lasts for 1 minute or until a wind of moderate or greater speed (at least 10 miles per hour) disperses it.

Tackle. Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 9 (2d6 + 2) bludgeoning damage. 

Smog (Recharge 5-6). Weezing exhales poisonous gas in a 20-foot cone.  Each creature in that area must make a DC16 Constitution saving throw, taking 28 (8d6) poison damage on a failed save, or half as much on a successful one.

Self-Destruct (Recharge 6).  Each creature in a 20-foot radius of Weezing must make a DC16 Dexterity saving throw.  A target takes 78 (12d12) bludgeoning damage on a failed save, or half as much damage on a successful one.  This attack also affects Weezing, it automatically fails on its saving throw and the attack ignores its resistances and immunities.