Huge monstrosity, neutral evil

Armor Class: 17

Hit Points: 168 16d12+64

Speed: 50 ft , climb: 40 ft

STR

23 +6

DEX

16 +3

CON

18 +4

INT

7 -2

WIS

14 +2

CHA

12 +1

Skills: Perception +6, Stealth +7

Damage Immunities: Lightning

Senses: darkvision 90 ft, passive Perception 16

Languages: Draconic

Challenge Rating: 11

Actions

Multiattack. The behir makes two attacks: one with its bite and one to constrict   Bite. Melee Weapon Attack: 1d20+10 to hit, reach 10 ft, one target. Hit: 3d10+6 piercing damage.   Constrict. Melee Weapon Attack: 1d20+10 to hit, reach 5 ft, one Large or smaller creature. Hit: 2d10+6 bludgeoning damage plus 2d10+6 slashing damage. The target is grappled (escape DC 16) if the behir isn't already constricting a creature, and the target is restrained until this grapple ends   Lightning Breath (Recharge 5-6). The behir exhales a line of lightning that is 20 feet long and 5 feet wide. Each creature in that line must make a DC 16 Dexterity saving throw, taking 12d10 lightning damage on a failed save, or half as much damage on a successful one.   Swallow. The behir 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 total cover against attacks and other effects outside the behir, and it takes 6d6 acid damage at the start of each of the behir's turns. A behir can have only one creature swallowed at a time. If the behir takes 30 damage or more on a single turn from the swallowed creature, the behir 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 fe et of the behir. If the behir dies, a swallowed creature is no longer restrained by it and can escape from the corpse by using 15 feet of movement, exiting prone.

Suggested Environments

Cavern Predators. Behirs lair in places inaccessible to other creatures, favoring locations where would-be intruders must make a harrowing climb to reach them. Deep pits, high caves in cliff walls, and caverns reached only by narrow, twisting tunnels are prime sites for a behir ambush. A behir's dozen legs allow it to scramble through its lair site with ease. When not climbing, it moves even faster by folding its legs beside its body and slithering like a snake. Behirs swallow their prey whole, after which they enter a period of dormancy while they digest. While dormant, a behir chooses a hiding place where intruders in its lair might overlook it.