Stegosaurus

Those iconic kite-shaped plates weren't actually attached to the spine — they were anchored in the skin, which is why scientists argued for years about how they were arranged. Grooves for blood vessels on the plate surfaces suggest they helped control body temperature or showed off to other dinosaurs, rather than working as armour.

The four deadly tail spikes — called the "thagomizer" — were genuine weapons. We know because an Allosaurus backbone was found with a healed puncture wound that perfectly matches a Stegosaurus spike! In life, these bony cores were covered in keratin (like your fingernails), making them even longer and nastier.

For such a massive animal, the skull is weirdly small and tube-shaped, with a toothless beak at the front for snipping plants and tiny leaf-shaped teeth in the cheeks. The brain was only about the size of a lime — one of the smallest brain-to-body ratios of any dinosaur ever discovered.

The back legs are nearly twice as long as the front legs, giving Stegosaurus that dramatic arched-back silhouette. This built-in slope was perfect for munching low-growing plants, though some scientists think it could have reared up on its back legs to reach higher leaves.

Tiny pebble-like bones have been found near the throat of one well-preserved specimen, revealing a flexible patch of hidden armour — like chainmail for the neck. These little bones are easy to miss, but they hint that Stegosaurus was way more armoured across its whole body than just the famous plates and spikes suggest.