19 (natural armor)
577 (33d20+231)
50 ft., climb 40 ft., swim 40ft.
Dex +11, Con +15, Wis +11, Cha +7
Intimidation +7, Perception +19, Stealth +11
lightning
blinded, charmed, deafened, frightened, stunned, unconscious
darkvision 120 ft.
Draconic
26
The behidra can hold its breath for 8 hours.
If the behidra fails a saving throw, it can choose to succeed instead.
The behidra has seven heads. While it has more than one head, the behidra has advantage on saving throws against being blinded, charmed, deafened, frightened, stunned, and knocked unconscious. Whenever the behidra takes 50 or more damage in a single turn, one of its heads dies. If all its heads die, the behidra dies. At the end of its turn, it grows two heads for each of its heads that died since its last turn. The behidra regains 20 hit points for each head regrown in this way. If the behidra takes fire damage, it must make a DC 25 Constitution saving throw. On a failure it doesn't regrow any heads on its next turn.
For each head the behidra has beyond one, it gets an extra reaction that can be used only for opportunity attacks.
While the behidra sleeps, at least one of its heads is awake.
The behidra exhales a line of lightning that is 60 ft. long and 10 ft. wide. Each creature in that line must make a DC 23 Dexterity saving throw, taking 22 (4d10) lightning damage on a failed save plus an extra 11 (2d10) lightning damage for each head the behidra has beyond one, or half as much damage on a successful one.
The behidra can use its Staggering Shockwave. It then makes as many bite attacks as it has heads.
Melee Weapon Attack: +16 to hit, reach 15 ft., one target. Hit: 13 (1d10+8) piercing damage + 5 (1d10) lightning damage. If the attack roll is a critical hit or exceeds the targets AC by 10 or more, the target is also grappled (escape DC 18). Until this grapple ends, the target is restrained, and the behidra can only make one bit attack against it per turn.
The behidra unleashes a debilitating surge of electrical and thunderous energy into the air surrounding it. Each creature of the behidra's choice that is within 60 feet of it must make a DC 23 Constitution saving throw. On a failure, until the end of the target's next turn, its speed is reduced to 0 and it can't take reactions. In addition, on its next turn, it can use either an action or bonus action, not both, and regardless of its abilities or magic items, it can't make more than one melee or ranged attack during its turn.
The behidra can take 3 legendary actions, choosing from the options below. Only one legendary action option can be used at a time, and only at the end of another creature's turn. The behidra regains spent legendary actions at the start of its turn.
The behidra moves up to its speed.
The next time the behidra takes damage from a creature that is within 15 feet of it before the start of its next turn, it can use the reaction granted by its Reactive Heads trait to make three bite attacks against that creature. A target can't become grappled by these attacks.
The behidra makes one bite attack against a Large 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 behidra, and it takes 28 (8d6) acid damage at the start of each of the behidra's turns. If the behidra takes 50 damage or more on a single turn from the swallowed creature, the behidra must succeed on a DC 25 Constitution saving throw at the end of that turn or regurgitate the creature, which falls prone in a space within 10 ft. of the behidra. If the behidra dies, a swallowed creature is no longer restrained by it and can escape from the corpse by using 30 ft. of movement, exiting prone. Blinded: • A blinded creature can't see and automatically fails any ability check that requires sight. • Attack rolls against the creature have advantage, and the creature's attack rolls have disadvantage. Prone: • A prone creature's only movement option is to crawl, unless it stands up and thereby ends the condition. • The creature has disadvantage on attack rolls. • An attack roll against the creature has advantage if the attacker is within 5 feet of the creature. Otherwise, the attack roll has disadvantage. Restrained: • A restrained creature's speed becomes 0, and it can't benefit from any bonus to its speed. • Attack rolls against the creature have advantage, and the creature's attack rolls have disadvantage. • The creature has disadvantage on Dexterity saving throws.
The behidra moves up to twice its speed, making one bite attack against each creature of its choice that is within 15 feet of it at any point during this movement. It has advantage on each of these attack rolls, but a target can't become grappled by these bite attacks.