Every so often an Invasion Event will appear on the map of American Dad! Apocalypse Soon and it provides you with an opportunity to pick up some extra cash or obtain a decent item by defeating the invaders. Check ou tour Invasion Event Guide to find out more about this feature.
Invasion Events will be indicated on the map by a UFO icon on the bottom-right of the screen which you need to tap on to participate. The invasions stages will then be clearly marked on the level map by UFO icons (see screenshot above), you just need to select one and do battle. If you are successful and manage to rebuff the invasion you will be able to collect your rewards chest. To participate in Invasion Battles costs food so if you have more than you need and don't want the excess to go to waste then entering the Invasionn Events is ideal.
Before engaging in combat in an invasion you may want to consider checking out comparative powers to get an idea whether you have a reasonable chance of being successful. If you struggle or think you will be unable to beat a particular Invasion you may need to level up your Rogers clones in the training room and equip them with better weapons, armour, and items. Successfully defeating all the invasions that are currently on the map will earn you a special chest that will contain a ticket for the Morning Mimosa tournament and a decent weapon or armour.
Check out our Morning Mimosa Tournament Guide to find out how you can earn a Royal Tournament chest and tournament tickets.