Emry Lurker of the Loch

“This spell costs 1 less to cast for each artifact you control. <br>When Emry, Lurker of the Loch enters the battlefield, put the top four cards of your library into your graveyard. <br>T: Choose target artifact card in your graveyard. You may cast that card this turn. <em>(You still pay its costs. Timing rules still apply.)</em>”