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

Endurance. If a fight lasts for over 6 rounds, the hyena has advantage on attack rolls.

Devour. If the hyena makes an attack against a creature that is lying down and hits, the creature must get up within 1 round or take 10 piercing damage, with 5 piercing damage added to each successful attack.

Scavenger. The hyena can attack a player on 0 hit points and still do damage.

Bite. Melee Weapon Attack: +2 to hit, reach 5 ft., one target. Hit: 1d12 piercing damage.

Whoop.  The hyena whoops, causing hyenas in a 60 ft. radius to come to its aid.

Giggle. The hyena giggles. The target must succeed on a DC 12 Wisdom saving throw or be frightened