The Reviver - a fast and agile Headcrab that, aside from being able to shoot electric balls, has the ability to electrically reanimate dead bodies, turning its host into a Revived Zombie.However, if the glowing heart on its underside gets shot, it will break apart instantly. The Armored Headcrab - a more fragile Headcrab that carries a hardened shell capable of protecting it even from gunfire.
![half life 2 cat half life 2 cat](https://i.pinimg.com/originals/15/78/9a/15789aa7cd7fa19091c9a5f6447d8ce5.jpg)
Also introduced in Half-Life 2, it turns its host into a Poison Zombie.
![half life 2 cat half life 2 cat](https://i.ytimg.com/vi/4sN5jvih9Po/hqdefault.jpg)
![half life 2 cat half life 2 cat](https://www.gamespot.com/a/uploads/original/1594/15949828/3646187-ee-cat.jpg)
Headcrabs can, apparently, be domesticated, as shown by Lamarr, Isaac Kleiner's pet Headcrab, who has been "de-beaked", and is said to be "completely harmless." Thus, removing the beak of Headcrabs renders them unable to perform their normal function of taking over humans, rendering them harmless and apparently less aggressive.