See Through the Fireeye

Sweep — Return any number of Swamps,
Mountains, and/or Forests you control to their
owner's hand. Then, you may discard that many
land cards. If you do, draw twice that many cards.
To most, the Cave of the Fireeye appears to be filled
with nothing but magma. To the chosen few, it is filled
with visions of a future no one else can fathom.