Hat trick

The rarely seen hat trick happens when a bowler dismisses three strikers with consecutive deliveries. These dismissals might all occur within one over, or may be split, an example being one striker being dismissed on the last ball of one over and the other two on the first and second balls of the bowler's next over. Sometimes that second over might be bowled on the following day, or it might be the bowler's first over of the batting side's second innings. It doesn't matter - all that is important is that the three dismissals occur from consecutive deliveries bowled by the same bowler in the same match.
The name is said to derive from a match played in 1858, when H Stephenson, playing for All-England in Sheffield, took three wickets in three balls. The crowd took up a collection to celebrate the achievement and bought a hat with the money that they then presented to the bowler.
The first hat trick in Test Match cricket occurred in only the third Test ever played, at Melbourne in 1879, when Australia's 'demon bowler', Fred Spofforth, performed the feat.
Only one bowler so far has taken two hat tricks in a single Test match. Tom Matthews of Australia did it in a Test against South Africa played in England in 1912, during what was called the Triangular Tournament.
There are also even rarer examples of four wickets being taken in four balls, and so on.