Jigglypuff's Final Smash starts when Jigglypuff breaks a Smash Ball. During it, Jigglypuff grows to multiple times her normal size. She takes up more space than the Iceberg. However, when she touches opponents, they take no damage. Because of her rubbery, flexible exterior, opponents bounce off of her when she is at the peak of her growing, potentially knocking people off stages when she bounces. She then starts to shout, and anyone touching her right after she shouts, will take damage (18%). Also even if someone isn't touching her, if they are close enough they will feel considerable knockback. She then shrinks to normal size.
- Jigglypuff's size before using the final smash affects the size she grows to. In giant mode, she grows to a size where only her face is visible on screen.
There is also a glitch in the game where the terrain is some stages (mainly Bridge of Eldin) touches Jigglypuff and knocks her out of the move yet he remains the same size she was when she was forced out of the Final Smash. Also, if Yoshi (or Kirby with Yoshi's ability) uses his Egg Lay on her after this, her size doubles. Her size resets for a split second when she uses the Final Smash again.
As a pun on her enormous size and on Giga Bowser this attack is often called "Gigglypuff" by fans.