Aliens, Fire, & Your Protector... A Marijuana Field.
The aliens are pissed-off at us. Get them high to help them forget about whatever the hell is causing the rage... Save the world with weed!
Swiping the marijuana field lights it on fire. If and alien inhales the smoke, it will get high, calm down and eventually pass out.
Double tap the field to use an asteroid to wipe out a group of aliens.