Nosk

"Mimics the shape of other creatures to lure prey to its lair. In the deepest darkness, there are beasts who wear faces stolen from your memories and pluck at the strings in your heart. Know yourself, and stay strong."

Nosk is a hidden boss in Hollow Knight. Its defeat is rewarded by one of the rare Pale Ores. Winged Nosk is its flying form.

Lore Nosk is a mysterious, shape-shifting, Infected beast hunting throughout Deepnest. It can mimic the shape of faces it finds in the memories of bugs, usually loved or departed ones, and can contort its body to assume a smaller frame. It hangs its prey, including Dirtcarvers, a Stalking Devout, and various Vessels, from the ceiling of its lair at the bottom of Deepnest.

In-game events When first encountered in Deepnest, Nosk looks exactly like the Knight. It can first be seen in an unreachable location before the long drop to the area's Hot Spring. After this, it can only be encountered in the hidden maze of tunnels leading to its lair. There it appears in several places and disappears before the Knight reaches it.

The way to Nosk's lair is littered with various dead bugs, their thoughts hinting at the creature's treachery. In the last tunnel, barriers of organic matter close one after another behind the Knight. Once reaching its lair, Nosk reveals its true form through a grotesque transformation, before roaring and beginning the fight.

When defeated, Infection bursts out of Nosk making it explode. It leaves behind only its counterfeit shell amidst puddles of Infection. The Knight can then collect a Pale Ore from a fossil in a cave further along.

Nosk, like all other strong creatures of Hallownest, is summoned to Godhome by the ritual of the Godseeker. It appears in the Pantheon of the Artist, but takes a winged form during the Pantheon of Hallownest. It first assumes the shape of Hornet and retains her shell as a face throughout the fight.

Behaviour and Tactics Nosk has four attacks:
 * Charge: Nosk makes a short screech, then rapidly scurries towards the Knight. It traverses the entire arena with this attack, and it does not stop if it hits the Knight.
 * Leap: Nosk leaps 1-3 times around the arena. It uses this manoeuvre to traverse the arena, but, at times, it also uses this to target the Knight.
 * Eruption: Nosk spews two blobs of Infection at its feet and sixteen more blobs, eight to its left, and eight to its right. They fly in parabolic arcs, leaving small gaps in between each blob after landing. Each blob lingers on the ground for half a second. Nosk always runs up to the centre of the arena to use this attack. This attack is always followed up by a Charge attack.
 * Rain: Nosk leaps into the ceiling of the arena, disappearing from sight, and rains blobs of Infection down on the Knight. Nosk stays out of sight for about six and a half seconds, dropping a blob or two every half second after the first blob. These blobs linger on the ground for half a second. Nosk can take about one and a half seconds off-screen before dropping the first blob. After this attack is over, Nosk drops down where the last blob landed. Nosk only uses this attack at 560 HP.

Nosk moves quite fast and takes up a lot of space which can make it challenging to avoid Nosk.

There are two spaces in the arena that can keep the Knight safe from most of Nosk's attacks and manoeuvres. They are the spaces right against the left and right walls of the middle platform. Standing here, Nosk Charges safely over the Knight. The left position protects the Knight when Nosk Charges to the left, during almost every Eruption, and during most Leaps. It is also a safe place to heal, even without Charms. The right position protects the Knight when Nosk Charges to the right.

The Shade Cloak is a very strong upgrade against Nosk, allowing the Knight to nullify all Charge attacks. Adding the Sharp Shadow Charm is a good way to add damage to those dodges.

Even though Nosk is out of sight during the Rain attack, its hitbox is still present in the ceiling and Charms such as Grimmchild and Glowing Womb can track and hit it. Furthermore, hitting it with the Nail in this state is also possible, and using charms like Longnail or Mark of Pride can make it easier when trying to do so.

If the Knight is caught by the Eruption Attack, a quick dash away is a good tactic for surviving. There is a sizeable gap between the blobs at Nosk's feet and the blobs that fly in the arc.

It is important to keep moving to dodge the Rain attack. Nosk attempts to track the Knight with these blobs, so standing in one place is dangerous. This is the only attack that is not nullified when hiding against the middle platform.

Nosk primes its Charge always with a quick small screech, using this sound to predict when it is about to Charge from off-screen can be very helpful. Be wary that Nosk most often prefaces an Eruption attack by Charging to the centre of the arena.

Spells can be very effective against Nosk. Desolate Dive/Descending Dark is a good response to all of Nosk's attacks, except the Rain attack. The Howling Wraiths/Abyss Shriek Spell is effective when hiding against the middle platform. It is also a good way to damage Nosk when it is in the ceiling during a Rain attack.

Location A breakable wall in the room directly west of the Deepnest Hot Spring reveals a secret section containing a Grub. Breaking another wall behind the Grub leads to the tunnels and into Nosk's lair. Either the Monarch Wings or Crystal Heart is required to access the hidden room. It is also possible to use the Nail to Nail-bounce on the Shade if it is lured near the first breakable wall.

Trivia
 * When it dies, Nosk drops the same shell that the Knight drops upon death, which can be hit around.
 * Winged Nosk references Nosk's original concept design where it had wings and a longer tail.
 * Nosk is shown in the Wanderer's Journal disguising itself with the body of a normal Husk bug as its head.
 * Another concept art of Nosk going by the file name of "Mimic Spider" and featured in a Team Cherry interview shows it with a regular-angled Knight head, longer tail and a lack of spines along its back.
 * It is important to note that, because the Shade will spawn in the same room as Nosk, once entering the room the only way to escape with an unbroken Soul meter is to beat the boss or use the services of Confessor Jiji.
 * Unlike other bosses, if the player returns to fight Nosk after death, the boss fight will immediately start instead of giving a proper boss introduction, it should also be noted after death, his name won't appear at all.

References

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