Corpse Creeper

"Parasitic beast that controls the body of its host after the host's death. The beasts of this land have found plenty of ingenious hiding places, but none so clever as the body of another creature! If you happen on such a beast, rejoice! You've hunted two creatures at once!"

Corpse Creepers are enemies in Hollow Knight. They are parasites which hide inside husks, controlling their host's body when the husk is defeated.

Behaviour and Tactics
When certain Husk Hornheads and Wandering Husks in Deepnest are killed, they reanimate as Corpse Creepers. This is signalled by the body of the corpse twitching a few seconds after death before sprouting legs and attacking. They will also emit a loud screeching sound cue after transformation which is useful to inform of a reanimation off-screen.

After they reanimate as Corpse Creepers, they will scuttle towards at the Knight very quickly. They can scale walls with ease, but cannot jump.

Great Slash helps to get rid of them easily. Once the corpse starts twitching, start charging up the Nail Art and strike as soon as it starts running. They are weak enough where even one Great Slash from the Sharpened Nail will kill it.

Location
The Corpse Creeper can only be found in Deepnest, mainly to the south of the Failed Tramway Bench.

Trivia

 * An easy way to tell if the husk will turn into a Corpse Creeper is by using the Dream Nail on it. Grimmchild will sometimes spit fire at a corpse that has a chance at reanimating, the fire making a "tink" sound when hitting the corpse. Corpses of defeated enemies will not have any Dream Nail dialogue, however, Corpse Creepers will, even before the telltale twitching starts.
 * There are two types of Corpse Creeper variants, the Husk Hornhead, and the Wandering Husk. Although there are Husk Bullies in Deepnest, these will never transform into Corpse Creepers.
 * The Corpse Creeper is one of the few enemies that have various different looks, but no change to behaviour, the others being the Siblings, the Fungified Husks, the Royal Retainers, and the Mistakes.

References

Trepacadáveres Трупонос Trupi Pełzak