Ayna Efendi, the Duplicadept

Whenever you cast a creature spell with
converted mana cost greater than the number of experience counters you have, you get an
experience counter.
At the beginning of your upkeep create a token
that's a copy of target creature on the battlefield
with converted mana cost less or equal to the
number of experience counters you have. Exile
it at the beginning of your end step.