Mimic Mirage: A support, attack, defensive, combo... I don't know, skill. Whatever you want to make of it?
Upon activating this skill, the exact location of your character is recorded. For the next # seconds, every action, block, skill and spell you take is recorded. At the end of the timer, the spell activates and the actions taken are repeated exactly by a transparent mimic of your character.
If you spend that time shielding and slowly walking backwards, the mimic will shield and walk backwards along the same path. If you cast two fireballs up and then whirlslash, the mimic will cast it's own pair of fireballs up at the same spot and whirlslash at the same spot. If you take a few swings at an enemy, get hit and knocked back, it will attack, stop and get knocked back as well. No skill or spell used takes MP from the actual character.
The trick to an ability like this is knowing how to time it properly, there is no assurance that the enemy will be anywhere near where they were # seconds ago, resulting in the mimic potentially slashing or launching meteors at thin air.
Ideal uses would be shielding for a while facing in one direction, then using that mirage as a blocker while you attack from behind it. Or using a skill such a Whirlslash over and over in a specific area, creating a temporary whirling death zone you can hide in and watch enemies take damage from if they approach. That's assuming any EP is left after charging up the Mimic Mirage, at least.
Higher charge levels could increase the number of seconds the mimic records for before activating, or it could summon another mimic during / after the first mimic to repeat the actions once again, or it could cause a secondary mimic to appear after the first one vanishess and repeat the actions taken by the actual player while the first mimic was repeating.
This seems like a ridiculous amount of fun, but perhaps too difficult to code in.