Ancestral Brontosaur

Ephemeral {7}{g}{g} (At the beginning of your upkeep, if this came under your control since the beginning of your last upkeep, exile it unless you pay its ephemeral cost. You may cast this card for as long as it remains exiled in this way.)
Trample, Reach
When Ancestral Brontosaur enters the battlefield, destroy target artifact or enchantment.