Brushing a cat is a tricky affair. Cats require consent for any kind of touching, and will attempt to murder you if you violate their bodily autonomy. This is essentially the core idea behind Brush Jjaemu, a free web game on itch.io. Like Flappy Bird, Brush Jjaemu is impossible for mere mortals, but some people easily rack up triple-digit scores. It's incredibly frustrating, but addictive.
Ignore the fact that the brush is a comb, which most cats would hate, and brush as fast as possible to rack up a high score. If Jjaemu gets annoyed, they will respond with an irritated look.

Fail to heed the warning, and this happens:

It's ridiculous that this game can pull off a jump scare every time, but it does. The game works on mobile, but can be buggy, so stick to desktop browsers if possible.
There is a site called brushjjaemu.org, but it is unclear if it is connected with the original game created by an artist who goes by artbyeori on itch.io and Instagram. The site is down as of this writing, so it's possible it is just not completely set up yet.
Previously:
• 'Almost Pong' is like a cross between Flappy Bird and Pong
• The Rise and Fall and Rise Again of Flappy Birds
• How 'crypto bros' appropriated Flappy Bird