Scholar of the Lost Trove
Creature - Sphinx
When Scholar of the Lost Trove enters the battlefield, you may cast target instant, sorcery, or artifact card from your graveyard without paying tis mana cost. If an instant or sorcery spell cast this way would be put into your graveyard this turn, exile it instead.
Well, so Oath turns into Tinker, but also could turn into Yawg Will or pretty much anything. This seems pretty cool.