Formers are Lambent humans that appear in Gears of War 3. These creatures are first encountered by Marcus Fenix and Delta Squad in the abandoned town of Mercy whilst they are searching for fuel and later on in the devastated city of Char.
Humans that had worked very closely with Imulsion were at the greatest risk of turning Lambent and townships such as Char and Mercy where Imulsion was refined would become infested with Formers as the Lambent Pandemic spread. Humans that had succumbed to the Lambent infection would develop chitinous growths all over their bodies and their bodily fluids would all be replaced with Imulsion, causing their bodies to glow from within.
Formers are zombie-like creatures that gather in large groups and frantically attack any non-Lambent creatures on sight with no regard for their own well-being. In fact, some Formers seem to retain some small degree of their human consciousnesses and can be heard crying out in agony and saying "Kill me".
Formers are very fast and always attack in large swarms, rushing at prey and leaping over obstacles, even demonstrating an ability to climb. They attack with their fingers that have elongated into claws and are able to quickly overwhelm prey with sheer numbers.
Luckily, Formers are very frail and they do not detonate violently as other Lambent creatures do. They can be killed easily with any weapon and will crumble to ash upon death, however, weapons with a narrow line of fire such as pistols or the Lancer are not as effective as Formers move very fast and can attack from any angle, making it difficult to hit them enough times before they close in for the kill. The Gnasher shotgun fires in bursts that can kill several Formers close together in one shot at close range and has a reasonable rate of fire. Charging Formers with the Retro Lancer's bayonet is also a good tactic for killing rows of them in a short time.