Detrimental Unchained

Trample, haste
At the beginning of the end step, sacrifice Detrimental Unchained.
Intern (Whenever you cast a spell that shares a type with this card, you may exile this card from your hand with 7 time counters on it. At any time, pay {x} to remove X time counters from it. When the last is removed, cast it from exile without paying its mana cost.)