Face Hugger

Simple. It attaches itself to someone's face.

Usually Nightmare Fuel from some horror film.

May be related to Face Full of Alien Wingwong.

Examples of Face Hugger include:

Comics

• The mind-control starfish of Starro the Conqueror.

Film

• The xenomorphs from Alien. Many later examples are homages.

Toys

• Krana and Krana-Kal of Bionicle.

Video Games

• Gligar and Gliscor from Pokémon.
• Metroids
• Headcrabs from the Half Life saga.
• X-COM Apocalypse has Brainsuckers, which in addition to appearing on their own are used as ammunition (in "egg" form) by certain aliens. The difference from other monsters of this sort is that they are spent in the attack, which irreversibly controls the victim on success, but otherwise inflicts no damage or status effects. Which creates sort of a weakness, since brainsuckers indiscriminately charge at the closest unfriendly target, so when this happens to be an android, they try to infect it anyway and are wasted. Making this harder to exploit seems to be one of the reasons for those brainsucker launchers.

Web Comics

• In Campus Safari, Chrome's miniwhip Aurla does a good impression of one. (Played for laughs)
• Sam Starfall pulls one of these off in an early strip of Cross Time Cafe. Hortmage finds it irritating and, maybe, disgusting.