The Euoplocephalus was a dinosaur that had several built-in defensive weapons at its disposal, including a heavy clubbed tail, spiky bone protrusions on the head and a back made of plate armor with protruding bone spikes that helped protect the dinosaur from bites and other forms of attack. Using its tail, the Euoplocephalus could not only fend off attackers but also do serious damage to their muscles, teeth and even bones. This herbivorous quadrupedal dinosaur is often called the "tank dinosaur" thanks to its extensive body armor, including its back plates and even armored eyelids, and its sturdy, stout anatomy.

The Euoplocephalus' body armor and clubbed tail were its primary means of defense; its teeth were small and built for eating plants, making them unsuitable weapons. As part of the ankylosaur dinosaur family, this tank like dino was one of several other dinosaurs with armored backs, though the Euoplocephalus was likely better protected than its relatives thanks to the extra protection provided by its armored eyelids and spiked face. This dinosaur was about the size of an adult rhinoceros, though its many weapons likely made it much heavier. Though it resembles the rhino in size, in practice, it likely had more in common with the armadillo.