How good are your powers of observation? Do you think you can spot what crazy thing happens to this guy when he's talking to some girls? Watch the video to test your skills!

Stuart Edge is back with something he calls the "Ninja Fast Person Switch Prank." This involves either him or his partner Calen Morelli going up to a group of girls and showing them pictures of guys on a dating app before asking them which they'd rather date. Now, what they're trying to find out is if people really pay attention to the person they're talking to and whether or not they'd notice if they switched places, all while wearing the same clothes. What ensues is both hilarious and amazing.

You have to admire how slick both Stuart and Calen's quick-change abilities. Some fancy footwork is involved during the distractions and the pair always exchange their jackets and hats. We suppose this could also work if they were just wearing the same hat and jacket already, but this way is more entertaining.

It's funny to see all of the double-takes and looks of disbelief on the faces of the girls after the pair switch it up. Some of them take a little while to notice anything has changed at all, but their reactions are priceless. Of course, not every transformation is seamless and the boys flub one or two up, which is also pretty fun to see.

All in all, it's an interesting experiment that shows us how well we truly pay attention to our surroundings. If nothing else, it shows that both Stuart and Calen can have pretty successful careers as professional ninjas. See more of Stuart's videos here and more of Calen's here.