Carnosaurs are huge, aggressive creatures that become almost impossible to control when they taste the blood of the enemy.
When this model (but not its rider) inflicts an unsaved wound upon an enemy model, it becomes subject to the Frenzy special rule. A model with this special rule may become Frenzied in this way even if it has lost Frenzy earlier in the game.
Note that this model’s rider does not gain a +1 modifier to their Attacks characteristic.