Alright, I spent some time thinking about a Final Smash, and the craziest thing I came up with is this:
Wish upon a Star:
You remember DK's Final Smash that makes you play a rhythm minigame or something like that?
This is... similar.
Upon activation, Gardevoir will go into a praying pose and the background turns darker, or even completely black. All other fighters are free to go on fighting during the next phase.
In this phase, all attacks that hit Gardevoir are phantom hits, no knockback, half damage.
Now, in the background, you will see a certain number of shooting stars shoot briefly across the sky one after another in random intervals.
Your task as the player is to press the button as soon as you see a shooting star appear, which might be hard because they shine only briefly, they are a bit small and they appear in random ( but visible ) locations in the background. You have to try to keep the button pressed from the very beginning to the very end of a star's duration. The better your timing, the better the effects. Of course, keeping the button pressed or mashing it won't do any good.
The point is that each star stands for a certain move that will be incorporated into the Final Smash combo. If you miss a star completely, the attack will either not be in at all or just have weak effects.
Once all stars have passed by, the background will dramatically turn light again and the following moves will occur in this order ( a textbox with the name of the move will pop up each time ):
Mirror Coat:
All damage done to Gardevoir while she was praying will be dealt back to those who inflicted it. Depending on the timing, it ranges from the same amount to double the amount, also, increasing knockback will be dealt ( hardly anything lethal, though ).
Psychic:
Following immediately after Mirror Coat, anything within the range of this attack will be taken by a psychic force and slammed diagonally downwards and into the direction of Gardevoir. It's pretty much a spike.
The range is quite large and, with perfect timing, it can take up all of the battlefield.
Rest:
Gardevoir falls asleep.
Due to its Synchronize ability, this instantly causes everyone on the battlefield to fall asleep as well, without exceptions!
This move is not assigned to a star and will be used regardless of your timing.
Wish:
If you managed to catch this star, it will return to wake up Gardevoir immediately.
Dream Eater:
And finally, everyone who's still asleep ( which should be everyone ), will get a bunch of their HP drained. The strength is dependent on the timing, of course. And, of course, the drained health is subtracted from Gardevoir's damage. Yay!
And since this move does no knockback, everyone should still be fast asleep and ready for some smashing.
...so, yeah, I'm crazy, alright.
EDIT: Yo, M&S Guy.
Thanks for putting effort into a moveset.
But there are some stats there I don't get... How do "defense" and "endurance" work?