Un'goro Tyrannosaurus Rex

Adaptation. The flora and fauna of Un'Goro are ever-changing and constantly adapting. If a property or action causes a creature to adapt, roll a d10 to determine which adaptation the creature acquires, depending on the number rolled. If the creature already has the rolled adaptation, roll a d10 until an adaptation the creature does not yet possess is rolled. The adaptation effect lasts until the creature finishes a long rest.

1. Elemental Protection. The creature gains immunity to damage from sound, acid, fire, cold, and electricity.
2. Resilient Organism. The creature gains immunity to damage from necrotic, poison, acid, and radiation.
3. Psychic Barrier. The creature gains immunity to damage from force or psychic attacks.
4. Durable Carapace. The creature gains immunity to non-magical piercing, bludgeoning, and slashing damage.
5. Sharp Fangs. Each time the creature hits with an attack that deals bludgeoning, slashing, or piercing damage, it deals an additional 2d6 damage of the same type.
6. Maneuverability. The creature gains a flying, swimming, and climbing speed equal to its normal speed (if the creature already has one of these speeds, it remains unchanged).
7. Camouflage. The creature makes Dexterity (Stealth) checks with advantage, and once per day can apply an effect that grants it invisibility, silent movement, and leaves no tracks for one minute.
8. Pounce/Bounce. The creature gains the ability to teleport up to 30 feet to an unoccupied space it can see as a bonus action.
9. Elemental Essence. As a reaction, when the creature takes damage from sound, acid, fire, cold, or electricity, it can gain resistance to that type of damage until the end of the round. Additionally, when the creature first hits with a melee attack on its next turn, the target takes an additional 1d6 damage of the same type.
10. Sharp Spikes. Each time the creature takes damage from a melee attack, the attacking creature takes 1d4 piercing damage.

Bloodthirst. Each time the Tyrannosaurus Rex hits with a bite or tail attack, it adapts. Additionally, if the Tyrannosaurus Rex kills a creature, it adapts twice.

Multiattack. The tyrannosaurus makes two attacks: one with its bite and one with its tail. It can't make both attacks against the same target.

Bite. Melee Weapon Attack: +10 to hit, reach 10 ft., one target. Hit: 33 (4d12 + 7) piercing damage. If the target is a Medium or smaller creature, it is grappled (escape DC 17). Until this grapple ends, the target is restrained, and the tyrannosaurus can't bite another target.

Tail. Melee Weapon Attack: +10 to hit, reach 10 ft., one target. Hit: 20 (3d8 + 7) bludgeoning damage.