AC 16 (natural armor)
HP 168 (16d12 + 64; bloodied 84)
Speed 60 ft., climb 40 ft., swim 40 ft.
Proficiency +4; Maneuver DC 17
Saving Throws Dex +6, Int +4, Wis +7
Skills Athletics +9, Perception +7, Stealth +6
Damage Immunities lightning
Senses darkvision 90 ft., passive Perception 17
Languages Common, Draconic
Spider Climb. The behir can use its climb speed even on difficult surfaces and upside down on ceilings.
Serpentine. The behir can move through a space as narrow as 5 feet wide, vertical or horizontal, at full speed, without squeezing.
ACTIONS
Multiattack. The behir makes a bite attack and then a constrict attack.
Bite. Melee Weapon Attack: +10 to hit, reach 10 ft., one target. Hit: 24 (3d12 + 5) piercing damage. If the target is a Medium or smaller creature grappled by the behir, and the behir has not swallowed anyone else, the target is swallowed. A swallowed creature is blinded and restrained , it has total cover from attacks from outside the behir, and it takes 21 (6d6) acid damage at the start of each of the behir’s turns.
If a swallowed creature deals 30 or more damage to the behir in a single turn, or if the behir dies, the behir vomits up the creature.
Constrict. Melee Weapon Attack: +10 to hit, reach 5 ft., one target. Hit: 21 (3d10 + 5) bludgeoning damage. The target is grappled (escape DC 17) and restrained while grappled. The behir can grapple two creatures at once.
Lightning Breath (Recharge 5–6). The behir breathes a line of lightning 5 feet wide and 20 feet long. Creatures in the area make a DC 16 Dexterity saving throw , taking 56 (16d6) lightning damage on a failed save or half damage on a success.
REACTIONS
Vengeful Breath (1/Day, While Bloodied). When struck by a melee attack, the behir immediately recharges and uses Lightning Breath, including the attacker in the area of effect.
Combat
The behir prefers to attack with surprise, often from the ceiling. It opens with a lightning bolt and then tries to bite, constrict, and swallow. It tries to escape when badly hurt, and usually has a bolthole nearby.
Legends and Lore
With an Arcana or History check, characters can learn the following:
DC 10 Behirs resemble dragons but are their mortal enemies.
DC 15 Behirs breathe lightning bolts and take no damage from lightning.
DC 20 Behirs have been known to swallow adventurers whole, and sometimes treasure gets left behind in their gizzards.
The behir is a blue-scaled, serpentine monster that creeps through dark tunnels on a dozen legs. It swallows prey alive when it can, and electrocutes fiercer foes with lightning breath.
Underground Travelers. A behir constantly ranges through miles of underground caves and tunnels, hunting for lone creatures and small groups to devour. It sleeps only while digesting such a meal. A behir can scuttle through narrow spaces and is usually aware of the closest secret passages and boltholes it can use for escape or ambush.
Although behirs don’t greatly value treasure, they collect some in their lair, and the relics of past meals are often found lodged in their gizzards.
Draconic Foes. Behirs are bitter enemies of dragonkind. Weaker than most adult dragons, they rely on stealth to prey on dragon eggs and young. Old legends have it that some ancient enemy of the dragons introduced behirs from another world to wipe out dragonkind—a failed effort which left the world’s underground places even more dangerous than before.
Although behirs prey on humanoid adventurers, they sometimes make use of them, revealing the location of a dragon’s lair, watching the ensuing battle from hiding, and attacking the victor. A behir rarely lies, so its directions can be trusted, though its motivations cannot.
1 From hiding, questions trespassers about whether they are friends or foes of dragons; if foes, it reveals the location of a dragon lair, and if friends, it attacks
2 Lying in wait in dark holes in the ceiling or wall
3 On the hunt
4 Slithering stealthily over and under ruins, such as the fallen statues of storm giants
5 Dormant after a large meal
6 Muttering to itself about its craving for a delicious dragon egg
1 Large bones. DC 13 Nature check: They are the bones of a young dragon.
2 A wall scorched by lightning
3–4 A five-foot-wide tunnel going straight up or down. DC 16 Perception or Investigation check: draconic tracks leading up or down
Behirs make their lairs in twisting caverns deep beneath the earth.
CR 11–16 Behir ; behir magus
Treasure 1,100 gp, 3,500 sp, broken jade dragon statuette (750 gp when repaired), 2 potions of greater healing , lantern of revealing