Teleportation Circle

When Teleportation Circle enters the battlefield,
tap target creature you control.
It does not untap during your untap step.
Once on your turn, you may put a creature from
your hand to the battlefield without paying its
cost if its converted mana cost is less than the
tapped creature's power.
"Zone is hot, standby for dynamic entry."
-Director Azmia of the Crypsis Clade