There's a tasty cake in the kitchen, and the ants living in the house have noticed this, too. A massive group of ants is on its way to the cake, planning to consume it. You want to foil their plans, and try to make the ants disappear by shooting a little ball at them, that's attached to a rubber band. If you hit a group of identical ants, they'll all disappear. If you hit one single, isolated ant, it will disappear as well. Some ants continually change colour; if you manage to hit these, the whole group will turn that colour and can be deleted in one shot. Just make sure that they won't reach the line!
Press the left mouse button while aiming, and release to shoot the little ball.