About
The Golden Snitch, often simply called the Snitch, is the third and smallest ball used in Quidditch. It is a walnut-sized gold-coloured sphere with silver wings. It flies around the Quidditch field at high speeds, sometimes pausing and hovering in place. The Seeker's goal is to catch the Snitch before the other team's seeker, which is worth one-hundred and fifty points. The game can only end when the Snitch has been caught, or by mutual agreement of the two teams' Captains; the latter is very rare, however, as one team would have to lose. Going off of Ginny Weasley's statement, it would appear Snitches fly at varying speeds, or at least can wear out.
The Quidditch rule also stated that only the two team's Seeker has the right to catch (or touch) the Snitch, any player other than the Seeker to do so commits a foul called a Snitchnip.
History
The Golden Snitch was originally not a ball, but a little magical bird called a Golden Snidget. It was introduced in 1269, when the Chief of the Wizards' Council, Barberus Bragge, unleashed a Golden Snidget during a Quidditch match, offering a reward of 150 Galleons to the player who caught the Snidget.
Thereafter, it became customary to set frightened Snidgets loose during games. As a tribute to Bragge, 150 points were given to the team that caught the Snidget. This Snidget-catching craze naturally harmed the bird's population (as Snidgets are very fragile birds, and a simple human grip is enough to crush them to death), but the wizarding community was then unwilling to stop this barbaric activity and ceased to use Snidgets only when the bird was labelled as endangered.
A replacement for the Golden Snidget was sought, and the skilled metal-charmer Bowman Wright invented the Golden Snitch to replace it. The Snitch weighed exactly the same as a Snidget, and its rotational wings imitated the bird's, allowing it to change direction and speed like its living counterpart.
One tale concerning the Snitch is that, during a match on Bodmin Moor in 1884, it managed to avoid capture for six months until both teams finally gave up in disgust at the performance of their Seekers. Cornish wizards and witches insist to this day that the Snitch is still wild in the area, which is possible due to its magical properties.
For Harry's seventeenth birthday, in 1997, Molly Weasley made him a Golden Snitch-shaped birthday cake, which was commented on by the then-Minister for Magic Rufus Scrimgeour.
Source: Fandom