The Foam Gun is a unique item that can be used as a weapon or as a way to access new areas. As the name suggests, the gun fires foam. No, not the sudsy kind. This special foam hardens on contact. Fire it at an enemy and you can freeze them in place. An immobile enemy is primed for a kill. Toss a grenade and it sticks to the foam and charges for a more powerful blast. As you can imagine, foaming up enemies and then tagging them with 'nades makes for an entertaining time. This is an especially useful tactic against some of the bigger bosses. Foam them up to temporarily immobilize them, shoot off a few grenades and watch the fireworks.