There are five mice that will pop up from time to time. You are the cat, and your goal is to catch them all. There are five mice, so if the one in the middle is there, it's the third. So, you have to press the 3 key to get rid of it. Instructions are also shown for 20 seconds before the game starts. Good luck!
This was just a random thing I made. It was supposed to be a maze, but I'm not that experienced in scratch yet.