Agni

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

Multiattack. The Agni 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 Agni can't bite another target.

Tail. Melee Weapon Attack: +10 to hit, reach 10 ft., one target. Hit: 15 (2d8 + 7) bludgeoning damage.

Leap. The Agni can reveal a pair of membranes on its back and leaps up to 60 ft and when it lands any creature in a 10 ft radius must make a DC 17 strength save or take 12 (2d6+6) and be knocked prone or half as much on a success and and is pushed to the nearest 5 ft square

Body Slam. The Agni performs a powerful charge, it lowers its head and charges crashing into the ground while moving its full speed. Any creature in the path must make a DC 17 Dexterity save or take 25 (6d6+7) damage and be knocked prone on a failed save, and none or a success.

Firebreath (Recharge 5-6). The Agni exhales fire in a 60-foot line that is 5 ft. wide. Each creature in that line must make a DC 17 Dexterity saving throw, taking 27 (5d10) fire damage on a failed save, or half as much damage on a successful one.