Belker

Multiattack. The belker makes 1 bite and 2 claw attacks.

Bite. Melee Weapon Attack: +7 to hit, reach 5 ft., one creature. Hit: 1d6+4 fire damage.

Claw. Melee Weapon Attack: +7 to hit, reach 5 ft., one creature: Hit: 1d6+4 fire damage.

Smoke Form. As a bonus action, a belker can assume a smoke form. This functions as gaseous form, except the belker has resistance to all damage and maintains its 50ft fly speed. While in smoke form, a belker can't use its regular attacks, but can use its Smoke Claws ability as an action.

Smoke Claws. If a belker in smoke form enters the space of a creature, the creature must make a DC 16 Constitution saving throw or inhale the smoke. On a failure, the target becomes poisoned and takes 3d4 fire damage. At the end of each of its turns, the target can repeat the saving throw, ending the effect and coughing the belker out to an adjacent square on a success. On a failure, the target takes 3d4 fire damage.

While inside, the belker can take no actions and has total cover against attacks and effects originating from outside the creature.