Open Sea Ormr

Open Sea Ormr CR: 13 (10000 XP)

Gargantuan ormr, unaligned

Armor Class: 17 (natural armor)

Hit Points: 248 (16D20 +80)

Speed: , swim: 60 ft

STR

23 +6

DEX

15 +2

CON

21 +5

INT

3 -4

WIS

12 +1

CHA

6 -2

Saving Throws: Strength +11, Constitution +9

Skills: Athletics +11, Perception +5

Senses: darkvision 60ft., passive Perception 15

Challenge Rating: 13 (10000 XP)

Hold Breath. The open sea ormr can hold its breath for 12 hours
Siege Monster. The open sea ormr deals double damage to buildings and structures
Apex Predator. Has advantage on saving throws against being frightened and cannot be frightened by creatures smaller than it.

Actions

Multiattack. The open sea ormr an make a bite and tail attack on its turn. It cannot make both attacks against the same creature
Bite. +11 to hit:, 10ft., , one target. Hit 33(4d12+7) piercing damage. If the target is a Huge or smaller creature, it is grappled (escape DC 19). While a creature is grappled in this manner, it is restrained. The ormr can use its bonus action to make another bite attack against a target grappled in this manner. The ormr cannot make bite attack against another target
Tail. +11 to hit:, 15ft., , one target. Hit 25(4d8+7) bludgeoning damage. If the target is a creature, it must succeed a DC 19 Constitution saving throw or be stunned until the end of its next turn.