The Infinity Clock

As an additional cost to casting The Infinity Clock exile any number of instants and or sorceries from your graveyard, put that many slumber counters on The Infinity Clock. The Infinity Clock doesn't untap during your untap step, remove a slumber counter during each of your upkeeps
{t}: Tap target creature, that creature can't untap until there are no slumber counters left on The Infinity Clock