Nagisa, Death's Prodigy

Deathtouch, menace
Whenever a creature you control attacks and isn't
blocked, put a +1/+1 counter on that creature
and draw a card.
Discard your hand: Untap all creatures you
control. Those creatures get +X/+X until end of
turn. Tap each creature you don't control with
mana value X or less. X is the number of cards
you discarded this way.