Giant mason wasps had a jet-black exoskeletons and mandibles that glowed red with heat. 
A bite from these creatures seared the flesh from because of the intense heat. 
A giant mason wasp’s stinger injected a dangerous toxin that caused the victim to pass out and fever. Unconsciousness lasted for a few days and the fever could kill. Those who survived were permantely weakened from the toxin. 
All kinds of fire was useless against these creatures. They could shoot a cone of fire from their mouths several times a day. 
These creatures lived alone in the wild within large structures made from dirt, sand and saliva. 
The females would mate once a month. After mating, the adult pair hunted down a large animal, paralyzed it, carried it back to her den, and the female would lay eggs on the creature. The female sealed the den to allow the eggs to hatch and feast in peace. 
Many parts of a giant mason wasp were useful for magical items, but killing one was bad luck so most waited for the insects to die naturally. A potion of fire breath could be made from their fire glands. Once powdered, their exoskeleton could be used for a potion of fire resistance or oil of fire invulnerability. The venom from their stinger was used as a potent venom, but lost potency after a week where it was then used as an antidote.