"Blackout challenge" is like a game where some people try to make themselves pass out by holding their breath or choking themselves. It's a very dangerous game that can cause serious harm or sometimes even death. It's important to remember that playing games like this can be very harmful to your body and it's best to avoid them entirely. It's always safer to play games that don't involve hurting yourself in any way. Remember to always talk to an adult or someone you trust if you're being pressured to participate in something that doesn't feel right or safe.