Emry, Lurker of the Loch

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