In a mode that feels like an evolution of invasions in From Software's Souls series, MGS V: The Phantom Pain will allow other players to invade your Forward Operating Bases (FOBs). These bases are important to your progress through the game, because they provide you with extra resources which you can use for expanding Mother Base (the hub for all your activities): hiring new soldiers, training them in various ways, and so on. A warning that your FOB is being invaded by another player can appear any time during missions (you can turn this off if you like). If you choose to accept the mission, you will immediately be transported to the base that's being invaded. If not, you can leave the FOB to defend itself using the turrets, drones, guards, and other security features you purchased for it, or even have someone on you friends list jump in to help defend it. No two FOBs will be the same, as each player will kit theirs out with a different arrangement of security features. There are probably plenty of players out there who will get just as much satisfaction from watching their base autonomously take out an invader as they would taking out the invader themselves. The invasion mode isn't to be confused with the team-based Metal Gear Online, which will be released shortly after the main game. Invasion mode is one-on-one, with no option for a co-op mode.