What is a bicycle kick (la bicicleta)?

Here is how it actually works. With the ball in the air, the player leaps so both feet leave the ground, leans head and shoulders backward as if falling onto their back, and swings the kicking foot up over their own face to whip the ball back over their head toward goal. The whole thing happens facing away from goal, which is exactly what makes it so improbable and so spectacular, and the player still lands hard on their back or shoulders.

It exists out of necessity, not showboating. When a ball drops or floats in behind you with no time to turn and settle it, the overhead kick is the only way to attack it cleanly while it is still airborne. The timing is brutal and the odds of whiffing entirely are high, so players try it rarely, which is why a clean one tends to win goal-of-the-season awards.

One thing that trips up Americans: the names. La chilena (the Chilean) is the common term across much of the Spanish-speaking world, while la bicicleta nods to the pedaling motion of the legs. English speakers mostly just say bicycle kick or overhead kick. It is fully legal, as long as you do not endanger an opponent with high, reckless boots near their head.