Thunderhand
Thunderhand is a move used by Luigi during the events of Mario & Luigi: Superstar Saga. It is the opposite of Mario's Firebrand. He is taught this by the Thunder God in the Thunder Palace, and is taught an advanced technique by the Jellyfish Sisters allowing him to be stuck to Mario and move faster. This can be used to pass through slow-moving spiked barrels and activate Boo Statues.
Thunderhand can power Lightning Orbs and be used offensively against enemies. In some cases, enemies will have a weakness to or can only hurt by the Thunderhand, such as the Piranha Plants on the Beanbean International Airport's runway. Mario and Luigi can also use the Thunder Bros. Bros. Attack, which involves Luigi jumping on Mario and lauching thunderbolts at enemies.