Armor Class 13
Hit Points 68 (8d10 + 24)
Speed 60 ft., fly 90 ft.
Damage Immunities fire
Senses passive Perception 11
Languages understands Abyssal, Common, and Infernal but can't speak
Challenge 3
Confer Fire Resistance. The nightmare can grant Resistance to Fire damage to a rider while it is on the nightmare.
Illumination. The nightmare sheds Bright Light in a 10-foot radius and Dim Light for an additional 10 feet.
Hooves. m +6, reach 5 ft. Hit: 13 (2d8 + 4) Bludgeoning damage plus 10 (3d6) Fire damage.
Ethereal Stride. The nightmare and up to three willing creatures within 5 feet of it teleport to the Ethereal Plane from the Material Plane or vice versa.
Monster Manual (2024), p. 226