The Severed Heads are grotesque, floating heads that fly by at the end of the third White Path accessible from White Desert A in an event. They appear only when the player goes inside the small building at the end of the tunnel, and they go away once the player exits, making them decorative characters.
The Severed Heads have a monochrome appearance just like everything else in the White Desert, with bright red blood flowing from where their heads are supposed to be attached. The first one is of a woman with dark, long hair, mouth open and eyes filled in with black. The other one is of a man wearing a distraught expression, with dark hair only on the sides of his head. They both merely float near the top of the screen, similarly to the UFOs and Falling Men.
Some fans have speculated that these are the parents of Madotsuki, or someone else related to her. This, along with their slightly bloody appearance, has lead some to interpret this as evidence for a sort of accident or other disturbing event in Madotsuki's past. This could connect to other themes of this in the game, such as the "train" besides Mars-san, Shitai-san, and Monoko's deformed appearance. The heads only appearing when Madotsuki is in the building could be thought of as her not wanting to confront this trauma.
The heads may also be related to an unused minigame, snippets of which were found in the thumbs files of version 0.04. Said thumbnails show images of a scrapped minigame named Severed Head PK in which the player seemingly kicks heads into soccer nets, featuring a rather crude art style compared to the rest of the game.