Skrelv's Hive is a rare Enchantment card from Phyrexia: All Will Be One Promos (PONE), collector number 34p. Current market price: $2.70 (foil $3.28), TCGplayer market prices via Scryfall.
At the beginning of your upkeep, you lose 1 life and create a 1/1 colorless Phyrexian Mite artifact creature token with toxic 1 and "This token can't block." Corrupted — As long as an opponent has three or more poison counters, creatures you control with toxic have lifelink.