Save the Queen

Save the Queen has been Donald's ultimate weapon throughout the series, with changing way to obtain it with each game. Goofy has a similarly named weapon, the Save the King.

Kingdom Hearts
It is obtained by winning the Hades Cup using only Sora (this mode is unlocked after winning the Hades Cup for the first time).

Kingdom Hearts stats
 * Description: A staff of immense magical and physical power.
 * Attack power: 9
 * MP effect: Raises max MP by 2

Kingdom Hearts II
This staff is obtained via synthesis. The staff requires Dense shards, stones, gems, crystals and orichalcum. There is another variant, Save the Queen +, which has no difference in power, but has a different ability.