I doubt that you can hold it steady enough at 20 feet…
Tripod would work, texaspro is right. You’d need to be focused on a set spot for more than 5 seconds, and some lasers can be focused to different ranges
I came so close to going this route and still might do it…
…in the sales corner of laserpointerforums lies madness!
I’ve got three cats and they won’t wear goggles; but DAMN do lasers look cool!