Mayael, Anima Unleashed

Whenever another creature enters the battlefield,
put an Aria counter on Mayael.
{r}{g}{w}, {t}, Remove X Aria counters from
Mayael: Reveal the top X cards of your library,
you may put a creature card from among them
with mana value X or less onto the battlefield.
Put the rest on the bottom of your library in
any order.