They look very similar to blueberries, but are dotted with white sparkles. According to Barry, Moon Berries only grow once every ten years.
In the episode "Cursed!," Barry was going to sell them. When Anne and Sprig accidentally bumped into Barry causing him to drop the berries, Barry pretended to not care if they got knocked down. But then later, Barry put a curse on Anne and Sprig, causing Sprig to get hair in his eyes, and causing Anne to start acting like a bird and becoming one. They both thought that Maddie put the curse on them because the other day, Anne helped Sprig break up with her.