Giant Whirlwyrm

Actions

Multiattack

The whirlwyrm makes two attacks: one with its bite and one to constrict.

Bite

Melee Weapon Attack: +10 to hit, reach 10 ft., one target. Hit: 22 (3d10 + 6) piercing damage.

Constrict

Melee Weapon Attack: +10 to hit, reach 5 ft., one Large or smaller creature. Hit: 17 (2d10 + 6) bludgeoning damage plus 17 (2d10 + 6) slashing damage. The target is grappled (escape DC 16) if the whirlwyrm isn't already constricting a creature, and the target is restrained until this grapple ends.

Thunder Breath (Recharge 5–6)

The whirlwyrm exhales a line of thunder that is 20 feet long and 5 feet wide. Each creature in that line must make a DC 16 Dexterity saving throw, taking 66 (12d10) thunder damage on a failed save, or half as much damage on a successful one.

Swallow

The whirlwyrm makes one bite attack against a Medium or smaller target it is grappling. If the attack hits, the target is also swallowed, and the grapple ends. While swallowed, the target is blinded and restrained, it has 3 against attacks and other effects outside the whirlwyrm, and it takes 21 (6d6) acid damage at the start of each of the whirlwyrm's turns. A whirlwyrm can have only one creature swallowed at a time.

If the whirlwyrm takes 30 damage or more on a single turn from the swallowed creature, the whirlwyrm must succeed on a DC 14 Constitution saving throw at the end of that turn or regurgitate the creature, which falls prone in a space within 10 feet of the whirlwyrm. If the whirlwyrm dies, a swallowed creature is no longer restrained by it and can escape from the corpse by using 15 feet of movement, exiting prone.