Avira, Avatar of Regrowth

When Avira, Avatar of Regrowth enters the battlefield, you may pay {1}{g}{g}. If you do,
sacrifice it.
{2}{g}{g}: Return Avira from your graveyard
to your hand.
At the beginning of your upkeep, if Avira entered
the battlefield exactly ten times this game, create
a hundred 1/1 green Saproling creature
tokens with protection from everything.