Behir is a Huge monstrosity with neutral evil alignment and Challenge Rating 11 in the 2024 SRD. This stat block includes AC 17, 168 hit points, speeds, traits, and actions.
Multiattack - The behir makes one Bite attack and uses Constrict.
Bite - Melee Attack Roll: +10, reach 10 ft. Hit: 19 (2d12 + 6) Piercing damage plus 11 (2d10) Lightning damage.
Constrict - Strength Saving Throw: DC 18, one Large or smaller creature the behir can see within 5 feet. Failure: 28 (5d8 + 6) Bludgeoning damage. The target has the Grappled condition (escape DC 16), and it has the Restrained condition until the grapple ends.
Lightning Breath - Dexterity Saving Throw: DC 16, each creature in a 90-foot-long, 5-footwide Line. Failure: 66 (12d10) Lightning damage. Success: Half damage.