That’s something you don’t see every day.

Will Zalatoris and Cam Davis were each penalized two shots for playing the wrong golf ball on the par-5 15th hole Sunday during the final round of The Sentry at Kapalua’s Plantation Course.

Rules expert Mark Dusbabek explained that Zalatoris played Davis’ ball, then Davis played Zalatoris. Neither player realized the error until they reached the green.

The penalty for playing the wrong ball is two shots, so the players had to return to their previous shots and replay from there.

Zalatoris and Detry both made double on the par 5.

This article originally appeared on Golfweek: Two PGA Tour players penalized for playing wrong balls at The Sentry