Using your hands, position your mouse on the cat and click on it. Hold on to the mouse without letting go. Drag it by moving your wrist to the "Damage" section to make it lose health. Click on it again to drag it to the "Heal" section to make the cat gain health.
Credit to @Speedrunner_Pro and @griffpatch for designing the health system. The rest of the code is all my own! Be sure to credit me and all the others that led to contribution in this project. On behalf of all of us, we'd appreciate it! :D