Matt, Lord High Artificier

When Matt, Lord High Artificier enters the battlefield, create a 0/0 colorless Construct
artifact creature token with "This creature gets
+1/+1 for each artifact you control."
Tap an artifact you control: Add {u}
{5}:Shuffle your library, then exile the top card.
Until end of turn, you may play that card without
paying it's mana cost.