Giga Mac was introduced as a special mechanic in the multiplayer mode for Punch-Out!! on Wii. When a player lands enough hits to the head, the player fills up a meter for their portrait. With the meter full, they can transform which shifts the scene from splitscreen into a traditional Punch-Out match layout with the Giga Mac transformed player being in the rear facing the camera. They deal much more damage but move slower and also gain a taunt. In return, they can be stunned when they miss. The player returns to normal once the meter runs out.
Super Smash Bros. series
Little Mac transforms into Giga Mac for his Final Smash. While Little Mac is transformed into Giga Mac, his attack and knockback is increased with several of his moves turning into 1-hit KOs. He loses access to his Power Meter but, the Straight Lunge has its charge time reduced. Additionally, he has much higher air speed and walk speed. After 11 seconds, he returns to normal.
Super Smash Bros. Ultimate
The move turned into a trapping attack as Giga Mac Rush where Little Mac transforms into the hulking form before lunging ahead and dealing a flurry of blows to whoever it hits. It is similar to Donkey Kong's new final smash, Jungle Rush except with less damage and knockback in exchange for the range.Giga Mac is also a Legend-class Spirit that increases Fist Attack and takes all 3 slots. It takes place on the Boxing Ring against a giant Little Mac with Super Armor in stamina mode.