Splinter Twin is a rare Enchantment — Aura card from Rise of the Eldrazi (ROE), collector number 165. Current market price: $7.77 (foil $38.99), TCGplayer market prices via Scryfall.
Enchant creature Enchanted creature has "{T}: Create a token that's a copy of this creature, except it has haste. Exile that token at the beginning of the next end step."