What are Spider Balls and why do we call them that? Drop one in water and find out as a multitude of multicolored balls will burst forth from the green sac and grow up to 100 times its size within hours! You can roll, throw, bounce, and try to squish the balls once they are hydrated- just like real spiders! Control the range of size by adjusting the amount of water you add. Sure to provide endless delight and days of fun!