Dementors!

There are seven positions on each Quidditch team, consisting of three Chasers, two Beaters, one Keeper, and one Seeker.

The chasers throw a twelve inch, red leather-covered ball – called the Quaffle – to one another, with the object of getting the Quaffle through one of the opposing team’s hoops. Getting the Quaffle through a hoop nets the team ten points.

The beaters’ job is to use their small clubs to beat away the hard, black, ten-inch balls – called Bludgers – that are enchanted to knock the players off their brooms. The Keeper’s function is to keep the other team’s Chasers from getting the Quaffle through a hoop.

The Seeker, who is usually the smallest and fastest player on the team, flies all over the pitch, trying to spot and then catch the tiny Golden Snitch, which is “… about the size of a large walnut.” The Golden Snitch has little wings, which enable it to hurtle around incredibly quickly. Both its speed and its tiny size make the Golden Snitch nearly impossible to see.

A Quidditch match can only end when the Golden Snitch is caught, which means that it can potentially go on for weeks (the record is three months). The team whose Seeker catches the Golden Snitch gets one hundred and fifty points, which frequently means that team also wins the match. However, if the Chasers of a particular team are exceptionally good – as was the case with the Irish team at the 1994 Quidditch World Cup – they can rack their team’s score up so high that one hundred and fifty points won’t matter. As one might expect with such a fast moving game, fouls happen all the time.