Mosquito
Mosquitoes of the genus "Toxorhynchites" never drink blood. This genus includes the largest extant mosquitoes, the larvae of which prey on the larvae of other mosquitoes. These mosquito eaters have been used in the past as mosquito control agents, with varying success.
Colossal squid
The colossal squid ("Mesonychoteuthis hamiltoni", from Greek "mesos" (middle), "onycho" (claw, nail), and "teuthis" (squid)), sometimes called the Antarctic squid or giant cranch squid, is believed to be the largest squid species in terms of mass. It is the only known member of the genus "Mesonychoteuthis". It is known from only a few specimens, and current estimates put its maximum size at long and weighing possibly up to , based on analysis of smaller and immature specimens, making it the largest-known invertebrate.