This worm survives the steepest temperature gradient known to animal life

The Pompeii worm lives in tubes on hydrothermal vent chimneys, with its head in relatively mild seawater while its tail presses against vent walls that can hit around 80°C. A fleece of heat-tolerant bacteria coats its back, possibly insulating it or feeding on its mucus. No other known animal is thought to withstand such an extreme temperature span across its own body.

— Wikipedia contributors, Alvinella pompejana — Wikipedia article