Drop bears are awakened koalas. They are differentiated from their mundane counterparts by their jet-black fur and elongated and sharp teeth and claws. They are omnivores and can thus eat both plants and meat; however they do have a dietary requirement of eucalyptus leaves.
Drop bears are carriers of HMHVV-II, but are not considered to be one of the infected. This is probably why drop bears don't require metahuman flesh and won't starve to death from abstinence.
Drop bears do not actively hunt their prey. Instead they conceal themselves in trees, aided by ther ability to bend visible light around them, effectively turning them invisible. Once their prey walks under the tree, they drop onto their target and attack with their claws and bites. Even if the prey survives, they are often infected with HMHVV-II.