Thessalhydra
Size
Huge
Monster Race
Monstrosity
Alignment
Unaligned
Armor Class
15 (natural armor)
Hit Points
172 (15d12 + 75)
Speed
6m, swim 6m
Attributes
STR
19 (+4)
DEX
12 (+1)
CON
20 (+5)
INT
5 (-3)
WIS
10 (+0)
CHA
7 (-2)
Features
Skills
Perception +4
Damage Resistance
Bludgeoning, Slashing, and piercing from magical weapons
Damage Immunities
Acid, Poison
Condition Immunities
Blinded, charmed, deafened, frightened, stunned
Senses
Darkvision 12m, passive perception 14
Challenge
8 (3,900 XP)
Abilities
Multiple Heads
The thessalhydra has 8 heads. While it has more than one head, the thessalhydra has advantage on saving throws against being blinded, charmed, deafened, frightened, stunned, and knocked unconcious. Whenever the thessalhydra takes 25 or more damage in a single turn, one of its heads dies. If all its heads die, the thessalhydra dies.
At the end of its turn it grows two heads for each of its heads that died since its last turn, unless it has taken fire damage since its last turn. The thessalhydra regains 10 hit points for each head regrown this way.
At the end of its turn it grows two heads for each of its heads that died since its last turn, unless it has taken fire damage since its last turn. The thessalhydra regains 10 hit points for each head regrown this way.
Magical Physical Resistance
The thessalhydra is a magical creature, it has resistance to any magical weapons that deal physical damage.
Reactive Heads
For each head the thessalhydra has beyond one, it gets an extra reaction that can be used only for opportunity attacks.
Actions
Multiattack
The thessalhydra makes as many bite attacks as it has heads, one maw attack, and one Acid Saliva attack. - Two heads can't attack the same creature in the same turn.
Flurry of Bites
Melee Weapon Attack: +7 to hit, reach 2m, one target. Hit: 7 (1d6 + 4) piercing damage plus 10 (4d4) poison damage.
Maw
Melee Weapon Attack: +7 to hit, reach 1m, one target. Hit: 9 (1d10 +4) piercing damage plus 5 (1d10) acid damage.
Tail Pincer
Melee Weapon Attack: +7 to hit, reach 2m, 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 6m of it. Each creature within 2m of that point must make a DC 15 Dexterity saving throw, taking 18 (4d8) acid damage on a failed save, or half as much damage on a successful one.
Legendary Actions
Description
The thessalhydra can take 2 legendary action, chosing 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 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.