Nightmare

Large, fiend, neutral evil

CR 3AC 13HP 68 (8d10)

Speed fly 90 ft, walk 60 ft

str: 18; (+4)
dex: 15; (+2)
con: 16; (+3)
int: 10; (+0)
wis: 13; (+1)
cha: 15; (+2)

Damage Immunities fire

Senses passive_perception: 11

Languages understands Abyssal, Common, and Infernal but can't speak

Traits

Confer Fire Resistance. The nightmare can grant resistance to fire damage to anyone riding it.

Illumination. The nightmare sheds bright light in a 10-foot radius and dim light for an additional 10 feet.

Actions

Hooves. Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit: 13 (2d8 + 4) bludgeoning damage plus 7 (2d6) fire damage.

Ethereal Stride. The nightmare and up to three willing creatures within 5 feet of it magically enter the Ethereal Plane from the Material Plane, or vice versa.