Kylox, Visionary Inventor is a rare Legendary Creature — Lizard Artificer card from Murders at Karlov Manor (MKM), collector number 214. Current market price: $0.15 (foil $0.22), TCGplayer market prices via Scryfall.
Menace, ward {2}, haste Whenever Kylox attacks, sacrifice any number of other creatures, then exile the top X cards of your library, where X is their total power. You may cast any number of instant and/or sorcery spells from among the exiled cards without paying their mana costs.