Venom organ failure. Many caterpillars have defensive venom glands associated with specialized bristles on the body, known as urticating hairs, which can be lethal to humans (e.g., that of the "Lonomia" moth), although the venom's strength varies depending on the species. Bees synthesize and employ an acidic venom (apitoxin) to cause pain in those that they sting to defend their hives and food stores, whereas wasps use a chemically different alkaline venom designed to paralyze prey, so it can be stored alive in the food chambers of their young. The use of venom is much more widespread than just these examples.
Alternative versions of Venom years from current comics continuity, Venom has been posing as "Edward Saks", the aide to the Mayor of New York. "Edward" has been manipulating the city ever since Spider-Man's disappearance in preparation for his eventual return; in the process, he had re-enlisted the Sinister Six, replicated his symbiote thousands of times (chalking it up to being "lonely"), and built a security system named "WEBB" which prevents New York citizens from escaping from the city, trapping them while allegedly protecting them from the outside world. Upon meeting him, Venom is quick to berate Spider-Man for abandoning him all those years ago