Skyswimmer

Skyswimmer CR: 13

Gargantuan monstrosity, unaligned

Armor Class: 18 (natural armour)

Hit Points: 216 16d20+48

Speed: 10 ft , fly: 60 ft

STR

23 +6

DEX

15 +2

CON

16 +3

INT

7 -2

WIS

12 +1

CHA

6 -2

Saving Throws: Con +8

Skills: Perception +6

Senses: passive Perception 16

Challenge Rating: 13

Amphibious. The skyswimmer can breathe air and water.

Actions

Multiattack. The skyswimmer makes three attacks: one with it's Bite and two with it's Slam.
Bite. Melee Weapon Attack +11 to hit, reach 10 ft, one target. Hit 22 3d10+6 piercing damage. If the target is a Large or smaller creature, it must succeed on a DC 19 Dexterity saving throw or be swallowed by the skyswimmer. A swallowed creature is blinded and restrained, it has total cover against attacks and other effects outside the skyswimmer, and it takes 21 6d6 acid damage at the start of the skyswimmer's turn. If the skyswimmer takes 30 damage or more in a single turn from the swallowed creature, the skyswimmer must succeed on a DC 18 Constitution saving throw at the end of that turn or regurgitate the creature, which falls prone in a space within 10 feet of the skyswimmer. If the skyswimmer dies, a swallowed creature is no longer restrained by it and can escape from the corpse by using 15 feet of movement, exiting prone.
Slam. Melee Weapon Attack +11 to hit, reach 30 ft, one target. Hit 19 2d12+6 bludgeoning damage.

Horrendously spiked multitoothed monstrosities, the Skyswimmers are a legendary species of leviathans that originated in the world of Ravnica. A few have escaped to other Material Plane worlds and terrify all those that see them. They feed on rocs, griffons, and any number of large flying creatures they encounter.

Suggested Environments

Many feet to miles in the air, gliding regularly through clouds to disguise their presence.