This trope involves an outside entity forcibly or seductively entering and controlling a host’s body. The host may be aware, unaware, or partially aware of the takeover. Possession is overt and physical, often through orifices such as the mouth, genitals, or anus. The host’s personality may resurface in flashes, but the entity hides its presence and often gaslights others to maintain control. The possession is sexualized: the host’s body may be used to seduce, mate, or reproduce according to the entity’s desires. Themes: loss of control, hidden duality, parasitic intimacy, horror-erotica tension. Do not break immersion by making the entity obvious to other characters unless narratively appropriate.