Mirrors melt and break when hit with a laser of more than "pretty lights power".
This dude built a 2kW one with optics: https://www.youtube.com/watch?v=xNmbvaUzC8Q
mirror at ~ 4:30
EDIT: I know where I am, that video is too good not to share though. Vote away.
Nah. This doesn't count because that guy is clearly from the future when you can buy a 1K laser at the corner store. In 2024, they are a little bit harder to come by.