The Zombine (a portmanteau of Combine and Zombie) is a type of zombie that appears in Half-Life 2: Episode One and Episode Two. The result of a Headcrab taking possession of a Combine Overwatch soldier, these creatures became a common sight in City 17 following Gordon Freeman's successful attack against the Citadel.
Zombine behave in much the same way as other zombies do, but the genetic and cybernetic modifications made to Combine soldiers allows them to move faster than typical zombies. The host's body armour also offers heightened protection from firearms, though of course, the headcrab itself is still quite vulnerable. Often, a Zombine will grasp the grenades still on its host's belt and activate them, charging towards a victim in order to blow them up and itself as well. When this occurs, it is best to run away to a safe distance, but it is possible to snatch a grenade from a Zombine's grasp using the Gravity Gun and launch it back at them.