Kira, Shocking Slime

Whenever a source deals damage to Kira, remove
that many charge counters from her, then she
deals that much damage to target opponent.
{3}, {t} or at the beginning of your upkeep: Put a
charge counter on Kira.
{t}, Remove X charge counters from Kira: Add X
mana of any one color. Kira deals half X damage
to any target, rounded down.