We made these friendly bombs from sponges (Dollar Store of course! Each bomb costs about $1 and takes about five minutes to make.). Safe, cool and fun no matter the age! Sponges come 2 or 3 to a pack. You need 2 sponges for a bomb. Cut each sponge lengthwise into 4 strips. Attach a rubber band to 4 of the strips, at the center. Do the same with another 4 strips. Attach both together at right angles so you have 8 strips total, making a bomb! And hey— when the battle ends, why not wash dad’s car with them for a great Father’s Day gift!