Giant Willow Aphid Tuberolachnus salignus

Size matters when you're an aphid, and this species just set the heavyweight record: the largest aphids on Earth at 5.8 millimeters. To put that in perspective, most aphids are barely visible specks, so fitting on a grain of rice makes this giant a true jumbo by aphid standards. These willow specialists have become so successful they've even acquired their own host-specific parasite — proof that even tiny insects can't escape being hunted.