Grimmkin Nightmare

"Terrifying member of the Grimm Troupe. As part of the Ritual, it gathers scarlet flame within its torch. It will relinquish the flame once defeated. "Dance and die and live forever, Silent voices shout and sing, Stand before the Troupe's dark heart, Burn away the Nightmare King.""

- 'The Grimm Troupe'

Grimmkin Nightmares are enemies in Hollow Knight. They are terrifying members of the Grimm Troupe who relinquish the flame they gathered within their torches to somebody who is worthy.

Behaviour and Tactics
Grimmkin Nightmares have five attacks, all of which (excluding teleport) deal two Masks of damage:
 * Charge: Charges directly at the Knight with extreme speed. Faster than the Grimmkin Master.
 * Flame Spray: Fires five fireballs at once. The pattern is identical to the Grimmkin Master's attack but each set moves faster. The Nightmare is then left vulnerable for a few seconds.
 * Flame Spiral: Summons five fireballs that spiral outwards from the Nightmare's body. This attack also leaves the Nightmare vulnerable.
 * Flame Pillars: Summons three pillars of fire underneath the Knight in succession. This attack also leaves the Nightmare vulnerable.
 * Teleport: Teleports to a random place a constant distance away from the Knight to perform an attack.

Like other Grimmkin spirits, Nightmares spawn when the Knight approaches a flame with the Grimmchild Charm equipped, at which point they become aggressive, following and attacking the Knight until they kill them or leave the current room. Nightmares deal two Masks of damage to the Knight with their attacks and thus require greater care.

All Grimmkin have the unique behaviour of following the Knight's movements exactly, staying a constant distance away from the Knight until acting. Grimmkin teleport after every attack, and after being damaged during their dash.

Their Charge attack can be dodged or Shadow Dashed through. It is possible, but risky, to attack them during this charge. The Sharp Shadow Charm makes it possible to damage them with minimal risk simply by dashing through them.

The Flame Pillars attack is easily avoidable with quick movement and dashes.

Location
Grimmkin Nightmares can be found in the Fungal Core, the Royal Waterways, and the Hive.

Trivia

 * When in combat with any Grimmkin, the Accordion Chase theme plays.
 * Cut Grimmkin Nightmare sprites existed in the game's files prior to the release of Lifeblood. It was a different version of the Charge attack animation where the Grimmkin can be seen as a flame with a mask without clothing.
 * During the fight with Troupe Master Grimm, Grimmkin Nightmares can be seen in the audience alongside Grimmkin Novices and Grimmkin Masters. They now share their colouration with the others instead of being the usual dark scarlet colour that is seen during their encounters with the Knight. However, during the battle with Nightmare King Grimm, regular-coloured Grimmkin Nightmares are the sole member of the audience.