Barnacle (Half-Life)

Barnacles are indigenous to Xen. They are sessile, living under overhangs, and have a long tongue that hangs several feet down. Whenever something accidentally runs into their tongue, they slowly drag them upwards to their awaiting maw. Always the opportunist, they can't afford to be picky, and will therefore eat everything that comes in contact with them. Their mouth is very big and takes up much of their bodies.

Appearance

 * Half Life