In Hindi and Urdu, doosra means "second" or "other".
Put simply, the it is the off-spinner's version of the googly.
Over the past five years, the world's top off-spinners have developed the doosra to baffle batsmen.
It looks very similar to a normal off-break, but rather than spin towards the bat, it goes the other way like a leg-break.
The doosra is bowled from the back of the hand with a lot of top-spin, but the wrist still moves in a clockwise direction.
It is a very difficult skill to master so you'll need plenty of practice if you want to learn how to do it.
However, its validity has been called into question because of the number of off-spinners who have been reported to the International Cricket Council for suspect actions bowling the doosra.
Sri Lanka's Muttiah Muralitharan, India's Harbhajan Singh and Pakistan's Shoaib Malik have all had to have their actions cleared by the ICC's Human Movement Specialist panel.
Sceptics claim the doosra cannot be bowled with a legitimate bowling action because it is physically impossible to do with a straight arm.
As with all spinners, variation is very important. So remember to change your flight and pace when you're bowling.