OK, here it is.
Sorry it took so long, but I got a little fancy, as I tend to do.
I got into investigating the sound effects, which I hadn't planned to do because it was sort of uncharted territory.
Anyway, now instead of the "shink!" sound it usually makes when Cecil draws his weapon to do the attack, it makes the "obtained item" noise; and instead of the dark wave sound effect, it makes the "cha-ching" noise you hear when buying stuff at a shop. These seemed more consistent with a money-throwing attack.

Anyway, the command is called "Coin." I couldn't think of anything better to call it that was 5 letters or less, but you can change that to whatever you want with FF4kster.
As discussed, it will attack all foes for an amount equaling 30 x the user's level.
The total damage done to all foes combined is the amount of GP expended.
If GP < Lv x 30 x Total # Monsters, then instead the damage will be Total GP / Total # Monsters (and the user ends up with zero GP).
If the player has zero GP, the character will simply walk forward, fist bump the air, then return to ranks.
Apply this patch to an
unheadered copy of
Final Fantasy II (U) (v1.1) [!]Enjoy!