White Sun's Twilight (PPONE-038) [Promo Pack: Phyrexia: All Will Be One Promos]

You gain X life. Create X 1/1 colorless Phyrexian Mite artifact creature tokens with toxic 1 and "This token can't block." If X is 5 or more, destroy all other creatures. (Players dealt combat damage by a creature with toxic 1 also get a poison counter.)