The Shambler is a new variant of the Divider, encountered only in Dead Space 3, created by disembodied Divider heads, now called Creepers.
The "Creeper" is a new name applied to the head of a Divider, similarly to the way female Slashers were re-named Spitters in Dead Space 2. Featuring an elongated tongue and three tendrils coming out of the neck, Creeper heads are capable of decapitating dead bodies and burrowing into their neck stumps to create "Shamblers". Shamblers are dead humans with firearms in their hands. They can attack from a medium range, however, being undead, Shamblers have incredibly poor aim, making it significantly less of a threat than regular human enemies.
If the Shambler body is sufficiently damaged, it will rip the Creeper out and toss it at its attacker. If the thrown head was dodged, and hits a wall/solid surface, it will become momentarily stunned, allowing the player to finish it off. Otherwise, if the Creeper hits its mark, it will attempt to rip off the victim's head and take the body as its own.