Rubinia Soulsinger is a rare Legendary Creature — Faerie card from Legends (LEG), collector number 256. Current market price: $15.55, TCGplayer market prices via Scryfall.
You may choose not to untap Rubinia Soulsinger during your untap step. {T}: Gain control of target creature for as long as you control Rubinia Soulsinger and Rubinia Soulsinger remains tapped.