Keen Smell. The leosaur has advantage on Wisdom (Perception) checks that rely on smell.

Pack Tactics. The leosaur has advantage on an attack roll against a creature if at least one of the leosaur's allies is within 5 feet of the creature and the ally isn’t incapacitated.

Pounce. If the leosaur moves at least 20 feet straight toward a creature and then hits it with a claw attack on the same turn, that target must succeed on a DC 14 Strength saving throw or be knocked prone. If the target is  prone, the leosaur can make one bite attack against it as a bonus action.

Multiattack. The leosaur makes two attacks: one with its bite and one with its claws.

Bite. Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit: 13 (2d8 + 4) piercing damage.

Claw. Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit: 14 (3d6 + 4) slashing damage.

Mutate. If the leosaur mutates, until the end of the round, all of the leosaur's allies within 120 ft. get +1 to their AC and can make two additional attacks.