Short-form cricket is accustomed to cutters, cross-seam deliveries and yorkers, but Sam Curran is doing his bit to add the 'moon ball' to cricket's lexicon. Sri Lanka's Pathum Nissanka became the latest victim of the bowler's ultra-slow ball in England's 19-run defeat in the first one-day international when he misjudged the speed and flight of Curran's delivery, clipping the ball straight to Liam Dawson.

A moon ball is an extremely slow, loopy delivery that relies on its flight and lack of pace to deceive the batter and disrupt their timing. Commonly associated with spinners, such as former England and Leicestershire off-spinner Jeremy Snape, the delivery is increasingly becoming a go-to option for fast and medium-fast bowlers too.

Curran, who has been deploying the variation to surprising effect in The Hundred and the T20 Blast, is able to drop his pace from 83mph to just 43mph with only a relatively subtle change to his action and release point. "You have to be creative, guys are developing so fast," Curran explained to former team-mate Stuart Broad on the BBC's For The Love of Cricket podcast. "I've worked so hard on trying to keep the arm speed the same and then I've got better at landing the ball at the right length," Curran added.

With the growth of T20 leagues and batters hitting harder and further, bowlers like Curran are having to develop new techniques and an effective slower ball to get their revenge. Former England quick Steve Harmison, who famously bamboozled Michael Clarke with a 65mph slow yorker in the 2005 Ashes, said Curran's ability to disguise the delivery is key to its success. "You can see his release point is a lot further back than [his off-cutter]," he said on TNT Sports.

"With the moon ball, he is just hoping that the batter gets lost in his movement and body shape. "He holds the ball between his first finger and his thumb, throws the ball in the air and tries to keep the same arm speed, but the ball comes out behind him much slower." Ironically, it is the lack of speed that kills. The delivery that fooled Nissanka was slower than all of spinner Rehan Ahmed's previous six balls in the innings.

"It does get hit, but I feel if a batter knows I can do something a little bit unique, like when you face a mystery spinner, they might have a bit more doubt," said Curran. Former England quick Steven Finn clocked speeds up to 90mph during his career, but says having a slow ball is crucial for any bowler. "You use it to outfox the batter and get one step ahead as a bowler," Finn told BBC Sport.

His former international team-mate Jade Dernbach, who developed a go-to back-of-the-hand slower ball to much success, agrees. "You have to have that sort of variety nowadays, the way one-day cricket is going," he said. "You can't just be a one-trick pony any more. The game is developing so quickly that you have to develop with it on a yearly basis." With bowlers like Curran continuing to find new ways to innovate, the moon ball in Colombo is just one more thing for batters to be worried about.

This article is the latest from BBC Sport's Ask Me Anything team. What is the 'designated batters' rule introduced by Big Bash League? When is the next Ashes series? What is net run-rate in cricket?