Random Up special kill

[internetmovieguy]

Some times Mario's Up special will kill the opponent. Is it a bug in the game or a very specific hit box in the moves animation? I think the hitbox is at the very end because thats the last place that connects when it randomly takes a stock.

 

[DtJ XeroXen]

There is indeed a slightly stronger hitbox both at the beginning of the move and at the very end. I used to use the latter hitbox to catch an opponent off guard high in the air to take a stock. I've never seen it kill other than extremely high up or at a very high percent though.