The thessalhydra is a strange and terrible creature with eight heads surrounding a large, circular mouth rimmed with jagged teeth. Its maw drips with acid, and its tail ends with a pair of sharp pincers. The thessalhydra is gluttonous and damaging to any environment.
Multiattack. The thessalhydra makes one maw attack and one Flurry of Bites.
Flurry of Bites. Melee Weapon Attack: +7 to hit, reach 10 ft.,one target. Hit: 7 (1d6 + 4) piercing damage plus 10 (4d4) poison damage.
Maw. Melee Weapon Attack: +7 to hit, reach 5 ft.,one target. Hit: 9 (1d10 + 4) piercing damage plus 5 (1d10) acid damage.
Tail Pincer. Melee Weapon Attack: +7 to hit, reach 10 ft.,one target. Hit: 10 (1d12 + 4) slashing damage, and the target is grappled. As an action, the target can escape the grapple by succeeding on a DC 14 Strength (Athletics) or Dexterity (Acrobatics) check (its choice). Until this grapple ends, the thessalhydra can't use its tail pincer.
Acid Saliva (Recharge 5-6) The thessalhydra spits a glob of acid at a point it can see within 30 feet of it. Each creature within 10 feet of that point must make a DC 15 Dexterity saving throw, taking 18 (4d8) acid damage on a failed save, of half as much damage on a successful one.
The thessalhydra can take 2 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. The thessalhydra regains spent legendary actions at the start of its turn.
Detect. The thessalhydra makes a Wisdom (Perception) check with advantage.
Tail Swipe. The thessalhydra makes a tail pincer attack.
Keen Smell. The demogorgon has advantage on Wisdom (Perception) checks that rely on smell.
Blood Frenzy. The demogorgon has advantage on melee attack rolls against any creature that doesn't have all its hit points.
Regeneration. The demogorgon regains 10 hit points at the start of its turn. If the demogorgon takes acid or fire damage, this trait doesn't function at the start of the demogorgon's next turn. The demogorgon dies only if it starts its turn with 0 hit points and doesn't regenerate.
A predator of the Upside Down, the demogorgon hunts the dimension looking for unfortunate creatures that find their way there. The size and shape of an adult humanoid, the demogorgon's mouth encompasses its face and unfolds like a blossoming flower.
Multiattack. The demogorgon makes three attacks: one with its bite and two with its claws.
Bite. Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 7 (1d8 + 3 piercing damage.
Claw. Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 12 (2d8 + 3 slashing damage.
Chameleon Skin. The troglodyte has advantage on Dexterity (Stealth) checks made to hide.
Stench. Any creature other than a troglodyte that starts its turn within 5 feet of the troglodyte must succeed on a DC 12 Constitution saving throw or be poisoned until the start of the creature's next turn. On a successful saving throw, the creature s immune to the stench of all troglodytes for 1 hour.
Sunlight Sensitivity. While in sunlight, the troglodyte has disadvantage on attack rolls, as well as on Wisdom (Perception) checks that rely on sight.
Multiattack. The troglodyte makes three attacks: one with its bite and two with its claws.
Bite. Melee Weapon Attack: +4 to hit, reach 5 ft., one target.
Hit: 4 (1d4 + 2) piercing damage.
Claw. Melee Weapon Attack: +4 to hit, reach 5 ft., one target.
Hit: 4 (1d4 + 2) slashing damage.