Urza's Sylex is a mythic Legendary Artifact card from The Brothers' War Promos (PBRO), collector number 40p. Current market price: $0.42 (foil $0.56), TCGplayer market prices via Scryfall.
{2}{W}{W}, {T}, Exile Urza's Sylex: Each player chooses six lands they control. Destroy all other permanents. Activate only as a sorcery. When Urza's Sylex is put into exile from the battlefield, you may pay {2}. If you do, search your library for a planeswalker card, reveal it, put it into your hand, then shuffle.