Urza, Lord High Artificer (Retro) [Modern Horizons] Wizard Your opponents can't block with

Your opponents can't block with creatures with even converted mana costs

Set: Kaladesh Promos Type: Artifact Creature — Construct Rare Cost: {11} This spell costs {X} less to cast

Set: Arabian Nights Type: Creature — Djinn Rare Cost: {1}{U}{U} You may choose not to untap Old Man of the Sea during your untap step

" —Von Yomm

Urza, Lord High Artificer (Retro) [Modern Horizons] Wizard Your opponents can't block withSet: Modern Horizons Type: Legendary Creature Human Artificer Rarity: Mythic Cost: {2}{U}{U} When Urza, Lord High Artificer 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 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.