Whir of Invention
Whir of Invention {X}{U}{U}{U}
Improvise (Your artifacts can help cast this spell. Each artifact you tap after you're done activating mana abilities pays for {1}.)
Search your library for an artifact card with converted mana cost X or less, put it onto the battlefield, then shuffle your library.
Latest set: [AER] Aether Revolt ( R · #49 )