Flukemarm

"An insatiable breeder. Has populated the Waterways with its kind. Its insides double as a nest for young Flukefeys. The desire to breed, to leave behind a memory of ourselves in the shape of a child... it seems to be etched deep into the heart of every living creature. I too have felt the pull of that base instinct."

Flukemarm is a hidden boss in Hollow Knight. Defeating her grants a new Charm, Flukenest.

Lore
Flukemarm is the mother of all Flukes infesting the Royal Waterways. Her body is used as a nest for young Flukefeys. Like her children, she was Infected and made hostile, although her condition as a breeder prevents her from leaving her cave.

In-game events
Flukemarm can be found suspended in a hidden cave below the pipework of the Royal Waterways. She lays dormant at first but shows hostility as soon as the Knight strikes her. Her defence relies on throwing Flukefeys at her foe.

When Flukemarm is defeated, the Infection within bursts out, making her explode. She leaves behind the Flukenest Charm.

Behaviour and Tactics
Flukemarm has the following singular attack:
 * Spawn: Flukemarm spits out two Flukefeys, each from any one of her orifices, telegraphed by Infection spewing out of the selected orifices. There can only be a maximum of 6 Flukefeys spawned at once.

The Knight is not locked into this fight, meaning that it is possible to escape the fight at anytime.

Most offensive tactics require upgrading the Nail enough (at least the Channelled Nail) to kill Flukefeys in one hit or using Fragile Strength/ Unbreakable Strength with at least the Sharpened Nail. Focus on killing the Flukefeys as quickly as possible and hit Flukemarm between spawns. The SOUL gained from the Flukefeys, can be used to cast the Vengeful Spirit/Shade Soul Spell to damage Flukemarm continuously.

Another offensive tactic is to repeatedly Nail-bounce off the top of Flukemarm while staying in the air, simultaneously killing her Flukefeys as they fly up to attack. This requires both control and balance but does not require any Charms; though, Longnail or Mark of Pride makes the process much easier.

Another offensive tactic is to use the Cyclone Slash Nail Art while falling down on either side of Flukemarm and repeatedly pressing ATTACK to maximize the number of hits. This can also kill Flukefeys as they spawn.

A defensive tactic involves using the Quick Focus and Stalwart Shell Charms to buy time, Soul Catcher and Grubsong to generate enough SOUL to heal, and Thorns of Agony to help kill the Flukefeys and occasionally damage Flukemarm herself if the Knight is close enough to her.

Abyss Shriek is very effective, especially when empowered by Shaman Stone. With this setup, three full casts without interruption kill Flukemarm.

The most important thing to avoid in this fight is falling into the water. Since the Knight cannot attack while swimming, they are left completely defenceless.

Location
Flukemarm is located in a hidden area of the Royal Waterways. Desolate Dive/Descending Dark is needed to break the breakable floor which leads to this area. Flukemarm can be found at the end of a tunnel in the southwest.

Trivia

 * Flukemarm can only be Dream Nailed when using noclip.
 * After Flukemarm's defeat, the upper part of the body is left in the arena. It can be attacked with the Nail or with Spells and can even be Nail-bounced on. However, this does not result in anything happening.