FOURTH

Deep beneath the ocean waves, squids lead lives that are far stranger than fiction. Every squid is born with a donut-shaped brain, a design choice by nature that forces their food to pass directly through the center of their "thinking ring" on its way to the stomach. To keep this unique anatomy powered, they utilize three separate hearts that pump bright blue blood, which is far more efficient than red blood at transporting oxygen in the freezing, high-pressure depths. Some deep-sea species have evolved "elbows" on their tentacles to keep them from tangling, while the elusive Colossal Squid sports eyes the size of soccer balls—the largest of any creature on Earth—allowing them to spot the faint, shimmering bioluminescence of approaching predators. Perhaps most impressive is their "smoke and mirrors" defense: when a squid release its ink, it doesn't just create a cloud; it often forms a pseudomorph, a thick blob of mucus and pigment that mimics the squid's exact shape and size, leaving confused predators attacking a ghost while the real squid jets away.