Karn, Scion of Urza
{4}
Legendary Planeswalker -- Karn
5
[+1]: Reveal the top two cards of your library. An opponent chooses one of them. Put that card into your hand and exile the other with a silver counter on it.
[-1]: Put a card you own with a silver counter on it from exile into your hand.
[-2]: Create a 0/0 colorless Construct artifact creature token with "~this~ gets +1/+1 for each artifact you control."
Urza, Lord High Artificer
{2}{U}{U}
Legendary Creature -- Human Artificer
1/4
When ~this~ enters, create a 0/0 colorless Construct artifact creature token with "~this~ gets +1/+1 for each artifact you control."
Tap an untapped 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 its mana cost.