Beast mode gives you a chance to turn the tables on the COG—assume the role of a ferocious Locust and assault the COG troopers in 12 waves of battle. Unlike Horde mode, where you can take your time defeating the assaulting Locust forces, in Beast, your time is precious. You have limited time to defeat all COG forces on the map before the Hammer of Dawn deploys against your team to lethal effect.
Dealing damage to COG forces and fortifications and downing or killing COG units gives you time bonuses. On many maps, these bonuses are mandatory for completing the later waves. As with Horde, you play Beast matches on the normal multiplayer Gears of War 3 maps. Because you assault the same bases that you can build in Horde, familiarity with that mode can help your offense in Beast.