Apex of the Hunt (Mythic Trait; Recharges after a Short or Long Rest). If Snapdax is reduced to 0 hit points, it doesn’t die or fall unconscious. Instead it regains 150 hit points, mutates twice on the table below.

Blood Frenzy. Snapdax has advantage on melee attack rolls against any creature that doesn’t have all its hit points.

Improved Critical. Snapdax's weapon attacks score a critical hit on a roll of 19 or 20.

Keen Sight and Smell. Snapdax has advantage on Wisdom (Perception) checks that rely on sight or smell.

Legendary Resistance (3/Day). If Snapdax fails a saving throw, it can choose to succeed instead.

Mutate. When Snapdax mutates it releases a coiling bolt of necrotic energy at one creature it can see within 30 feet of it. The target must make a DC 21 Constitution saving throw, taking 22 (4d10) necrotic damage on a failed save or half as much damage on a successful one. Snapdax then gains temporary hit points equal to the amount of damage the target takes.

Pounce. If Snapdax 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 21 Strength saving throw or be knocked prone. If the target is prone, Snapdax can make one claw attack against it as a bonus action.

Multiattack. Snapdax makes four attacks, one with its bite, two with its claws, and one with its gore.

Bite. Melee Weapon Attack: +12 to hit, reach 5 ft., one target. Hit: 19 (2d12 + 6) piercing damage. 

Claw. Melee Weapon Attack: +12 to hit, reach 5 ft., one target. Hit: 22 (3d10 + 6) slashing damage. 

Gore. Melee Weapon Attack: +12 to hit, reach 5 ft., one target. Hit: 16 (3d6 + 6) piercing damage.

Heightened Reflexes. Creatures provoke an opportunity attack from you when they enter your reach.

Snapdax can take 3 legendary actions, choosing from the options below. Only one legendary action option can be used at a time and only at the end of another creature’s turn. Snapdax regains spent legendary actions at the start of its turn.

Claw Attack. Snapdax makes a claw attack.

Daunting Roar. Snapdax can let out an especially menacing roar. Each creature of its choice within 60 feet of it that can hear it must succeed on a DC 18 Wisdom saving throw or become frightened of Snapdax until the end of the creature’s next turn.

Nightmare Prowl. Snapdax moves up to half its speed. This movement doesn’t provoke opportunity attacks.

If Snapdax's mythic trait is active, it can use the options below as legendary actions for 1 hour after using Apex of the Hunt.

Call the pride. Snapdax lets our a roar summong either,1 Cubarden, 1 Huntmaster Liger,  1 Patagia Tiger, or 1 Regal Leosaur, 

Will of the All-Hunter. One creature other than Snapdax gets a +2 to STR (to a max of 30), and a +1 to AC (to a max of 25) for the next 24 hours.