Map The Twisted Heavens

Draw a card for each color of mana used to cast
this spell, then discard X cards.
If three or more colors of mana were used to cast
this spell, return up to one target instant or
sorcery card from your graveyard to your hand.
"The sun we see is the same, but the stars, the stars!
My charts are useless!"
- Lum, the navigator