We've already had one headbutting incident at this World Cup (looking at you, Pepe), but Cameroon defender Benoit Assou-Ekotto took it to the next level when he came at his own teammate.
Cameroon was in the midst of a 4-0 beatdown at the hands of Croatia and was already down a man thanks to a first-half red card. Assou-Ekotto made matters worse when he confronted Benjamin Moukandjo, fro and all.
Cameroon lost 1-0 to Mexico before Wednesday's beatdown. Things may not get better for them as they'll face Brazil in the final group game.