Head Four Ways, with Grizelda.

Grizelda’s head can exist independently when detached. As one of the undead, she doesn’t require air, blood, or food to survive, and can speak without lungs or vocal cords thanks to the dark magic that animates her. Although her mobility is limited in this form, the prehensile tentacles slithering within her skull can be used for ambulation when extended from her neck.

The primary purpose of those tentacles, however, is to bind her to a host body so that she can assume control. The tips can expand and contract at will, allowing them to pierce soft tissue like a needle and anchor themselves with barbs. Once buried in place, she can use these tube-like extremities to inject her ichor, allowing her to manipulate the flesh and feel its nerve endings as if they were her own.

While it’s technically possible for her to possess a living host, trial and error have led her to the conclusion that it’s generally preferable to exsanguinate them and remove the problematic head first.