Wart-like Appendages. Through wart-like appendages on its under lower lip the Adult Crimson Splitjaw can read the flow of the air. While the Adult Crimson Splitjaw is in the air it has adavantage against dexterity saving throws.

Bite. Melee Weapon Attack: +8 to hit, reach 10 ft., one target. Hit: 21 (3d10 + 5) piercing damage, and the target is grappled (escape DC 15) if it is a Large or smaller creature. Until this grapple ends, the target is restrained, and the banderhobb can't use its bite attack on another target. 

Tail Whip. Melee Weapon Attack: +8 to hit, reach 25 ft., one target. Hit: 21 (3d10 + 5) piercing damage, and a target must make a strength saving DC 14 or be knocked back by 10 ft. and fall prone.

Swallow. The Adult Crimson Splitjaw makes a bite attack against a Medium or smaller creature it is grappling. If the attack hits, the creature is swallowed, and the grapple ends. The swallowed creature is blinded and restrained, it has total cover against attacks and other effects outside the banderhobb, and it takes 14 (3d8) acid damage at the start of each of the Adult Crimson Splitjaw's turns. A creature reduced to 0 hit points in this way stops taking the acid damage and becomes stable. The Adult Crimson Splitjaw can have only one creature swallowed at a time. While the Adult Crimson Splitjaw isn't incapacitated, it can regurgitate the creature at any time (no action required) in a space within 5 feet of it. The creature exits prone. If the Adult Crimson Splitjaw dies, it likewise regurgitates a swallowed creature.

Air flow evasion. While the Adult Crimson Splitjaw is in the air it can add 3 to its AC when targeted by a ranged attack.