Occasionally, Mushrooms grow to every player's yard. These can be picked up by a free worker, picking it up takes 20 seconds to complete. When picked up, it takes a few seconds to disappear. Each time when a worker picks up a Mushroom, they get one Kaboom 3000 rarely, displaying at the center of your yard (Not the Town Hall). These take up space however, be sure to pick them all up when redesigning.