Aleuna, Leading the Charge

At the beginning of your post combat main
phase, reveal the top X cards, where X is the
amount of opponents you attacked this turn.
Choose one of those cards and put it into your
hand, put the rest on the bottom of your
library in a random order. You may cast a
copy of the chosen card until end of turn.
Copies you cast costs {1} less for each
opponent you dealt damage to.