Arda Turan lost his cool - and his footwear - during Atletico Madrid's ill-tempered Copa del Rey loss to Barcelona.
The Turkish international, seemingly incensed at not being awarded a free-kick, flung one of his boots in the direction of an assistant referee.
It is not clear if Turan was aiming for the official but the flying object missed by some distance.
Turan, 27, escaped a red card but was booked by referee Jesus Gil Manzano following the 48th-minute incident.
Wednesday's contest at the Vicente Calderon Stadium was a fiery affair, with Atletico finishing the match with nine men.
Midfielder Gabi was sent off during the half-time break, claiming he was given a second yellow card for arguing with the referee. Defender Mario Suarez was dismissed late on following a second booking.
Barcelona won the game 3-2 to seal a 4-2 aggregate victory and a place in the semi-finals, where they will face either Villarreal or Getafe.