All Seeing Eyes

Whenever a creature enters the battlefield under
your control you may look at the top card of your
library, you may exile it face down(You may look
at it). Target opponent guesses if that card costs
less than or equal to, or more than the creature
that entered the battlefield. If they guess right
each player draws a card. If they guess wrong
you may sacrifice the creature and play the
exiled card without paying its mana cost.