From the Super Mario Wiki
Lightning is the fifth captain command in the Minion Quest: The Search for Bowser mode of Mario & Luigi: Superstar Saga + Bowser's Minions. The highest-costing command in the game, it costs seven CP to use. When used, the captain will send cascading lightning bolts on all members on the opposing squad, shrinking them, similar to Lightning in the Mario Kart series. The effect varies for all squad members.