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Large beast, unaligned
Pounce. If the allosaurus moves at least 30 feet straight toward a creature and then hits it with a claw attack on the same turn, that target must succeed on a DC 13 Strength saving throw or be knocked prone. If the target is prone, the allosaurus can make one bite attack against it as a bonus action.
Bite. Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit: 15 (2d10 + 4) piercing damage.
Claw. Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit: 8 (1d8 + 4) slashing damage.
The allosaurus is a predator possessing great size, strength, and speed. It can run down almost any prey over open ground, pouncing to pull creatures down with its wicked claws.