The characters are wasps from the devastated nest of Ys’drktha. The other survivors from the cataclysm are being held and tortured in the pits of the neighbouring Ak’thaan nest, being slowly dismembered and eaten by drone wasps or fed to the writhing masses of larvae.
Actually a real-world fungus, just heard about it. A fungus that tastes well and all, no ill effects. UNLESS you consume some beverage, even 3 (three) days after eating it. Then you become really sick, pains, vomiting, all the fancy stuff. Was really used to cure alcoholism. May be a joke or to make sure the heroes spend their time focused on the mission.