Red Chaos Emerald

{t} Sacrifice this artifact. All your creatures get
+3/0 and trample this turn.
{t} Sacrifice this artifact. Ping target
opponent for 10 dmg.
{t} Sacrifice this artifact. Exile 7 cards from the top
of your library.
You can play your exiled cards
for 0 mana.
If you decide to cast a nonland spell this way,
this has to be the only spell casted this turn by you.