Scion of Sheltering Soil

Unless you would control fewer creatures
than there are creature cards in your graveyard,
Scion of Sheltering Soil isn't a creature.
Whenever Scion of Sheltering Soil enters the battlefield or attacks, return a permanent card
from your graveyard to you hand.
If one or more cards would leave your graveyard,
you may put them on the bottom of your library
instead, then mill 2.