Riku, of Shifting Reflections

Whenever you copy a spell, put a +1/+1 counter on Riku.

Remove X +1/+1 counters from Riku, where
X is at least one, choose one:
• Riku becomes a copy of target creature with
mana value X or less until end of turn, except
it has these abilities.
• Create X copies of Riku, except the tokens
aren't legendary, and they have haste. Exile
them at the beginning of the next end step.