Pounce. If the allosaurus moves at least 15 feet straight toward a creature and then hits it with a claw attack on the same turn, that target must succeed on a DC 15 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.

Overwhelm. The allosaurus has advantage on attack rolls against creatures that are two size categories smaller than it.

Innate Spellcasting: The allosaurus' spellcasting ability is Wisdom (spell save DC 12). It can innately cast the following spells, requiring no components:

2/day each: enlarge/reduce

Magic Weapons. The allosaurus' weapon attacks are magical.

Bite. Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 16 (2d10 + 5) piercing damage, or 18 (2d10 + 1d4 + 5) when enlarged.

Claw. Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 9 (1d8 + 5) slashing damage, or 11 (1d8 + 1d4 + 5) when enlarged. The target must make a DC 14 Constitution saving throw, taking 10 (3d6) poison damage on a failed save, or half as much damage on a successful save.