Nosk

Nosk is a minor antagonist and optional boss in Hollow Knight. It is a mimic, and takes the form of loved ones to lure unsuspecting prey into its lair.

History
Sometime before The Radiance plagued Hollownest with the Infection, Nosk was an animal that predated by shape-shifting against the prey of Deepnest. Following the Infection, Nosk changed its attributes and became mentally sadistic, toying with its prey by mimicking their lost beloved ones before killing them and hanging their corpses in its den.

Nosk can be found in the Deepnest, behind a breakable wall in the room left to the Deepnest Hot Spring, which the Knight can reach with the Monarch Wings or a Super Dash. Breaking a second wall to the left of the room with the imprisoned Grub leads to narrow tunnels, where a Vessel similar to the Knight can be seen in a place where the Knight cannot reach, vanishing once the Knight makes it to where their counterpart stood. This continues until the Knight enters a new room, where the wall behind them suddenly closes, forcing them to continue forward into a dark room filled with hanged corpses of bugs and their impersonator in the middle on an elevated platform.

Upon entering Nosk's lair, the imposter reveals itself with a hissing screech and transforms into its true self before attacking the Knight. Nosk attacks the Knight by charging, leaping, or by spewing acidic blobs of Infection from its abdomen, which it either does by erupting, or by jumping to the top of its lair, where it will drop blobs for about six seconds before jumping back down. By cornering themself against the edge of the center platform, the Knight will be protected by Nosk's charges and some of its leap attacks. Continue attacking until Nosk is defeated.

Defeating Nosk grants the Knight a Pale Ore, which can be used by the Nailsmith to upgrade the Knight’s nail.

Trivia

 * Prior to the Hidden Dreams DLC, Nosk’s only attacks were to charge and leap.
 * Several of Nosk’s previous victims can be seen in the background hanging from webbing, including Dirtcrawlers, a Stalking Devout, and even Vessels similar to the Knight.
 * One of these Vessels is lacking a head, possibly where Nosk acquired its disguise.
 * Nosk drops the same mask the Knight drops upon death.
 * Nosk is one of the few enemies that does not toggle dialogue when struck with the Dream Nail, instead letting out ellipsis.