The Masked Ones

{b}{b}: Target a creature your opponent controls.
Until end turn, The Masked Ones becomes a
copy of target creature, except its base power and toughness are 3/1.
{b}, Sacrifice a Singer: Return The Masked Ones
from your Graveyard to your hand.
They are the spren of parshmen long dead. They are
their kings, their lighteyes, their valiant soldiers from
long, long ago. The process is not easy on
them.