Pimu the alpha male chimpanzee of the troupe of Lake Tanganyika, Tanzania, being beaten to death by his own underlings

While boobies incubate their eggs and raise their young, Galapagos vampire finches peck away at the birds eating bits of their skin and flesh. Boobies barely offer any resistance as the finches' current behavior possibly evolved from a more mutualistic relationship where finches ate their parasites.