Knuckleball

A knuckleball or knuckler is a baseball pitch thrown to minimize the spin of the ball in flight, causing an erratic, unpredictable motion. The air flow over a seam of the ball causes the ball to change from laminar to turbulent flow. This change adds a deflecting force to the baseball, making it difficult for batters to hit but also difficult for pitchers to control and catchers to catch; umpires are challenged as well, as the ball's irregular motion through the air makes it harder to call balls and strikes.^[1] A pitcher who throws knuckleballs is known as a knuckleballer.