There are several different species of Black Leaf Bugs, each resembling the shed leaves of various deciduous trees. They all share a few traits in common: swarm behaviour, poor flight, behavioural mimicry of leaves blown by the wind, defenses, feeding modes, and means of reproduction.
In appearance, Black Leaf Bugs resemble a cluster of fallen leaves, blown about by the breeze. It is not uncommon to see more than one species represented within a swarm. When they encounter a large animal however, they quickly swarm and paralyze it. Individually, their bites are small, and their paralytic venom weak. However, in a swarm, the collective toxin can quickly subdue even a cow, and keep it paralyzed until the larvae have devoured it. The adult females feed on animal blood, leaving pinprick sized holes on the paralyzed victim, barely noticable even under scruitiny. Adult males, ironically, feed on dead vegetable matter. All however, swarm and inject their paralyzing toxin.
The eggs hatch within a few hours, and the tiny larvae burrow their way deep inside the victim’s flesh. The paralyzed victim is eaten from the inside-out, while it is still alive and conscious for the early stages. The skin & bones are not consumed by the developing larvae, but muscle & soft tissues are. This leaves (pun unintended) the victim in the latter stages resembling a horrific type of scarecrow—the frame & skin are stuffed with wriggling vile leaves. These burst out from the victim, and become a new swarm.