Luigi (SSB4)/Up smash
An upward headbutt. Quite fast for a smash attack, and its sweetspot is strong enough to KO middleweights at 135%. However, its sourspot is much weaker because of its lower damage output, and thus very unreliable for KOing. Like Mario and Dr. Mario's up smashes, it renders his head intangible throughout its duration. His nose hurtbox, however, is still vulnerable. It can also function well as a "slide" smash out of a dash, thanks to Luigi's very low traction. Opponents are launched towards Luigi when hit. It's very safe thanks to low endlag. However, it punishable out of shield.