Gastonia

Huge, flat triangular spikes stuck out sideways from the shoulder area like deadly warning signs. These bony weapons meant that any predator trying to attack from the side—like the fearsome Utahraptor—would basically be throwing itself onto a row of blades. No biting required; just standing there was dangerous enough.

The hip region was covered by a solid sheet of armor plates fused together into one rigid shield. This bony shell protected the back end and vital organs from predators sneaking up from behind. A related armored dinosaur from Europe called Polacanthus had the same feature, hinting they inherited this defense from a common ancestor.

Curved, blade-shaped armor plates ran along both sides of the body, angled outward and upward. Instead of just a few isolated spikes, these formed an almost continuous cutting edge along each flank—like a living wall of knives. Scientists pieced together their arrangement from jumbled bones of multiple individuals found buried together.

Small teeth shaped like little leaves with jagged edges were perfect for snipping off low-growing plants, but not for heavy chewing. Unlike duckbilled dinosaurs with their hundreds of grinding teeth, this plant-eater probably relied on a powerful gut to break down tough vegetation after swallowing it.

Built like a tank, this dinosaur had a super-wide body that hugged close to the ground. That low center of gravity made it nearly impossible for predators to knock it over and get at its softer belly. The proportions of its leg bones and the spread of its armor show just how broad and stable this living fortress really was.