Huge Beast
Armor Class 15
Hit Points 57 (6d12+18)
Speed walk +60
Challenge 3
Senses passive Perception 11
Bite. Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit: 17 (3d8 + 4) slashing damage. If the allosaurus moves at least 10 feet towards its target before making this attack it gains advantage on the attack.
Source: Level Up Advanced 5e Monstrous Menagerie · OGL/Open