The tyrannosaur moves 30 meters per movement action.

On the first round of combat, if the environment allows the creature to hide, the target must succeed on a Wisdom check (DC [15 + Dexterity modifier]) or be Surprised. If it successfully attacks a surprised target, the creature deals +1d6 damage and any creature with lower Strength than its own is Knocked Prone. The creature gains a +5 bonus to all Stealth checks and to Initiative.

When the creature succeeds on an attack roll of 15-20 on the d20, it seizes its prey between its jaws or claws and immediately deals an additional free attack. If the target's Strength is equal to or lower than the predator's, it is also Knocked Prone and Restrained. To break free, the victim must succeed on an opposed Strength check on its turn, which costs a movement action (and another to stand up if successful).

When it uses its Devour ability, the creature can swallow whole a target at least 1 size smaller than itself. The victim must succeed on an opposed Strength check or fall directly into the monster's stomach. A swallowed character takes 3d6 damage from suffocation and acid each round. It can attack with a weapon no larger than a dagger by succeeding on a DC 15 Strength check each round; the attack suffers a -5 penalty to the attack roll and damage is halved.