The ability to
forcibly enter the body of another through the orifices or any opening a body happens to have. Sub-power of Infestation.
The user can enter forcibly the body of an opponent through target's orifices, usually the mouth. They can also enter an opponent's body from any other opening that is present. While inside an opponent's body, the user can either destroy them from the inside out or take over their body.
A Facehugger (Aliens/Alien vs. Predator) orally infests a human with a Xenomorph embryo.
Super Buu (Dragon Ball Z) pours himself down Smitty's throat...
...eventually causing him to explode.
Inque (Batman Beyond) in the process of pouring herself down Batman's throat to suffocate him.
A Khan Worm (Supernatural) infesting a human's ear.
Xeexi (Sym-Bionic Titan) invading Lance's body through the mouth.
Yeerks (Animorphs) take control of their hosts by infesting the ear canal.
Davy Jones (Pirates of the Caribbean) kills Ian Mercer by using his tentacles to enter the orifices of his face, thus suffocating him.
Baby (Dragon Ball GT) possesses Goten by entering his body through a cut.
Jason Voorhees (Friday the 13th), in the form of a demonic worm, attempts to transfer himself from one host body to another by forcing himself down said body's throat.
The Squirrelanoids (Teenage Mutant Ninja Turtles; 2012 TV series) reproduce by forcing themselves down a host's throat and dividing into two within the host body's stomach.
Brain worms (Teenage Mutant Ninja Turtles; 2012 TV series)
Envy (Supernatural), like all demons, can possesses a human by entering through the mouth.
A Bug (The Matrix) invading Neo's body through his navel.
The Thousand (Marvel Comics) can infest human bodies through their mouths, devour their innards, and use the leftover skin as a disguise.
Noriaki Kakyoin's (JoJo's Bizarre Adventure Part III Stardust Crusaders) Stand, Hierophant Green can control a person by entering their bodies.