Cosmo.sx is a wonderful Space-themed MMO Kizi game where you can give out damage to the planets that are scattering around the galaxy in order to increase your skills. When the planet deals damage, it will reduce its size, and when the size gets smaller, it will become a large black hole which you must stay away from. All black holes are very deadly. So, you shouldn't come close to them. Try to boost your skills and gradually reach the top spot on the leaderboard. Have fun!