Ghiroo, The Superhydra

+9

Grihoo can hold its breath indefinitely.

Grihoo has an infinite number of heads. Whenever it takes 60 or more damage in a single turn, one of its heads dies. On its next turn, the number of attacks it makes as part of its Multiattack decreases by one (to a minimum of three) and it can't use its Snappy Frenzy. At the end of Grihoo's turn, it replaces all of its missing heads that died since its last turn.

If Grihoo fails a sasving throw, it can choose to succeed instead.

5/DAY

Grihoo has advantage on saving throws against spells and other magical effects.

Grihoo's weapon attacks are magical.

Grihoo can take one reaction on every turn in a combat.

Grihoo makes five bite attacks.

Melee Weapon Attack: +18 to hit, reach 30 ft., one target. Hit: 20 (2d10+9) piercing damage plus 11 (2d10) force damage.

Grihoo unleashes a flurry of bites in its vicinity, making one bite attack against any number of creatures within 30 feet of it, with a separate attack roll for each target.

Grihoo chooses one creature it can see within 120 feet of it. The target must succeed on a DC 21 Charisma saving throw or be teleported inside of Grihoo's stomach. While inside Grihoo, the creature is blinded and restrained, it has total cover against attacks and other effects outside Grihoo, and it takes 28 (8d6) acid damage and 28 (8d6) force damage at the start of each of Grihoo's turns. If Grihoo takes 60 damage or more on a single turn, it must succeed on a DC 17 Constitution saving throw at the end of that turn or expel all creatures that were teleported inside of it, teleporting them to a random space on the ground within 60 feet of Grihoo. If Grihoo dies, a creature that was teleported inside of it is no longer restrained and can escape from the corpse by using 60 feet of movement, exiting prone.

D5

When a creature Grihoo can see or hear within 300 feet of it casts a conjuration spell or magically summons a creature, a Grihoo interrupts the casting or summoning, causing it to fail and have no effect. Grihoo then regains hit points equal to 15 times the spell slot's level, if it interrupted a spell, or equal to the challenge rating of the creatures being summoned, if it interrupted a summoning.

The grihoo can take 5 legendary actions, choosing from the options below. Only one legendary action can be used at a time and only at the end of another creatures' turn. Grihoo regains spent legendary actions at the start of its turn.

5/TURN

Grihoo makes one bite attack.

Grihoo magically teleports, along with any equipment it is wearing or carrying, up to 120 feet to an unoccupied space it can see.

Grihoo channels the overwhelming weight of infinity, crushing each creature inside of it. A swallowed creature must make a DC 24 (Constitution) saving throw, taking 55 (10d10) force damage on a failed save, or half as much damage on a successful one.