Electrostatic Djinn.

Electrostatic Djinn enters the battlefield with X
static counters on it.
Remove X static counters from Electrostatic
Djinn: exile cards from the top of your library
until you exile a instant or sorcery card with converted Mana cost X, you may cast that card
without paying it's Mana cost, then, shuffle all
cards exiled with Electrostatic Djinn into their
owners library.