Nightmare Dragon (5e Creature)
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Large dragon, neutral evil
Saving Throws Dex +4, Con +8, Wis +4, Cha +5
Amorphous. The dragon can move through a space as narrow as 1 inch wide without squeezing.
Multiattack. The dragon makes three attacks: one with its bite and two with its claws. It can make one tail attack in place of its two claw attacks.
Bite. Melee Weapon Attack: +8 to hit, reach 10 ft., one target. Hit: 15 (2d10 + 4) piercing damage.
Claw. Melee Weapon Attack: +8 to hit, reach 10 ft., one target. Hit: 11 (2d6 + 4) slashing damage.
Tail. Melee Weapon Attack: +8 to hit, reach 10 ft., one target. Hit: 13 (2d8 + 4) bludgeoning damage plus 3 (1d6) fire damage.
Frightful Scream (Recharge 5-6). The dragon lets out a bloodcurdling cry that pierces the mind of any who hear it. Each creature within 40 feet of the dragon must make a DC 16 Wisdom saving throw. On a failed save, a creature takes 14 (4d6) psychic damage and is frightened. On a successful save, a creature takes half as much damage and isn't frightened. An affected creature may repeat the saving throw at the end of each of its turns, ending the effect on itself on a success. If a creature's saving throw is successful or the effect ends for it, it cannot be frightened by this dragon's Frightful Scream for the next 24 hours.
Nightmare dragons are stealthy creatures that can assume a partially gaseous form at will. They hunt from ambush, starting battle by unleashing a horrifying scream and then moving in to rip their prey apart with their claws and teeth, though if the dragon doesn't feel threatened, it will toy with its victims, relishing their fear as it moves in for the kill.