To catch the cat use your mouse to click it but you have to be fast to catch him. And I almost forgot press the green flag to make the cat reappear.
The cat is trying to catch the red spot. Don't use your hands that would be cheating. Try to catch the cat and have fun! Catch The Cat Level 2 is already out. Here's the link. Have fun! https://scratch.mit.edu/projects/416412422