Biorhythm [Onslaught] Urza's Saga As Thief of Blood enters

As Thief of Blood enters the battlefield

(They can't be blocked except by artifact creatures and/or black creatures

Set: Commander's Arsenal Type: Enchantment Rarity: Common Cost: {2}{U} Whenever an opponent casts a spell

Niv-Mizzet

Set: Aether Revolt Prerelease Promos Type: Legendary Artifact Rarity: Mythic Cost: {6} Whenever Gonti's Aether Heart or another artifact enters the battlefield under your control

Biorhythm [Onslaught] Urza's Saga As Thief of Blood entersSet: Onslaught Type: Sorcery Rarity: Rare Cost: {6}{G}{G} Each player's life total becomes the number of creatures they control. "I have seen life's purpose, and now it is my own." Kamahl, druid acolyte