A kickboxing instructor sprayed a class of 10 year olds with BB gun pellets, a court heard.
Peter Sheridan, 46, told Exeter Crown Court he "did it for a laugh" and did not intend to hurt any of the children.
Sheridan was found guilty of possessing an imitation firearm at a sports centre in Kingsbridge, Devon, and was given a conditional discharge.
Spencer Wilding, who played Darth Vader in Rogue One, gave a personal reference to Sheridan.
Mr Wilding said Sheridan was "devoted to helping others and supporting the community".
The court heard that former European kick boxing champion Sheridan, who used to train with Mr Wilding, sprayed the six children with dozens of 6mm pellets from a battery-powered rifle.
Three children complained they had small marks where they had been hit by pellets.
The court heard Sheridan said it was an attempt to make them run around the hall at the Quayside Leisure Centre faster.
"It was just a game," he said.
"It was a toy gun. Of course I did not intend to shoot the children."
Staff at the centre found 70 pellets on the floor of the hall after the lesson ended.
Sheridan, of Kingsway Park, Kingsbridge, was cleared of three counts of assault and ordered to pay £500 costs.
Judge David Evans told him: "You acted immaturely. You were like an over-excited child."