????? is event #51 in Super Smash Flash 2. It is the last event in the game and can only be played if the player has obtained A rank or higher in every other event.
Playing as a character of choice, the player must defeat two Master Hands, one on each side of the stage, on Final Destination. Both Master Hands have 500 health points, and the player has 1 stock. Fireworks will spawn periodically, and the player can use them to damage the Master Hands. However, the Fireworks can be hit by the Master Hands themselves, in which case they will deal damage to both the player and the Master Hands.
The ranking the player receives is based on how much time the event takes to be completed. The specific conditions for this are listed below.
> 1:36 '66
The second Master Hand is most likely supposed to represent Crazy Hand.
In this event the second Master Hand's laser attack will only deal damage at the start of the lasers, which are also bugged.
It is possible to get KO'd and fail the event even if the Master Hands have been defeated.