Huge undead, neutral

Armor Class: 19 (natural armor)

Hit Points: 226 (18d12 + 90)

Speed: 40 ft , fly: 80 ft , swim: 40 ft , climb: 40 ft

STR

22 +6

DEX

14 +2

CON

20 +5

INT

14 +2

WIS

14 +2

CHA

14 +2

Saving Throws: DEX (+6), CON (+10), WIS (+7), CHA (+8)

Skills: Insight (+7), Perception (+12), Stealth (+6)

Damage Vulnerabilities: Fire

Damage Resistances: Necrotic

Damage Immunities: Poison

Condition Immunities: Charmed, Frightened, Incapacitated, Poisoned

Senses:

• Blindsight. 60ft.
• Darkvision. 120ft.
• Keen Sight and Smell. The Adult Flood Dragon has advantage on Wisdom (Perception) checks used to find things using sight or smell.
• Passive Perception: 22

Languages: understands the languages it knew in life but can't speak

Challenge Rating: 15

Actions

• Multiattack. The Adult Flood Dragon can use its Frightful Presence. It then makes three attacks; one Bite attack and two Claw attacks.
• Bite. Melee Weapon Attack: +11 to hit, reach 10ft., one target. Hit: 24 (4d8 + 4) piercing damage. The target must make a DC 18 Constitution saving throw or suffer the effects of the Flood Infection.
• Claw. Melee Weapon Attack: +11 to hit, reach 5ft., one target. Hit: 13 (2d8 + 3) slashing damage.
• Tail Shot. Ranged Weapon Attack: +11 to hit, range 20/60, one target. Hit: 15 (2d8 + 5) piercing damage.
• Frightful Presence. Each creature of the Adult Flood Dragon's choice that is within 120ft. of it and aware of it must succeed on a DC 16 Wisdom saving throw or become frightened for 1 minute. A creature can repeat the save at the end of each of its subsequent turns, ending the effect on itself on a success. If a creature saves successfully or the effect ends for it, the creature is immune to this feature for 24hrs.
• Infectious Breath (Recharge 5-6). The Adult Flood Dragon exhales a cloud of infectious Flood spores in a 60ft. cone. Each creature in that area must make a DC 22 Constitution saving throw or suffer the effects of the Flood Infection.

Legendary Actions

The Adult Flood Dragon can only 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 Adult Flood Dragon regains spent legendary actions at the start of its turn.

• Detect. The Adult Flood Dragon makes a Wisdom (Perception) check.
• Tail Attack. The Adult Flood Dragon makes a Tail attack.
• Wing Attack. The Adult Flood Dragon beats its wings. Each creature within 10ft. of the Adult Flood Dragon must succeed on a DC 19 Dexterity saving throw or take 13 (2d6 + 5) bludgeoning damage and be knocked prone. The Adult Flood Dragon can then fly up to half of its flying speed.