We'd love to see him do this in a game next season!
The French defender isn't exactly known for his flair or shooting prowess (or his defending sometimes), so what he managed to do in training has left us, and plenty of Gunners fans, shocked.
Koscielny starts off with a few kick ups but then finishes it off with a truly audacious rabona shot which flies into the top corner of the net!
Stunned Arsenal fans left some belting comments on the Facebook video, with one suggesting: "This is why wenger won't sign a striker." While another reckons Arsene Wenger should: "Put him next to Giroud upfront."
Who knows what Wenger has in mind for the 29-year-old defender, but we're hoping to see him pull out some silky skills when the new Premier League season starts next weekend, with the Gunners taking on West Ham United at the Emirates.