Merieke Ri Berit is a special Legendary Creature — Human card from Time Spiral Timeshifted (TSB), collector number 95. Current market price: $2.88 (foil $32.53), TCGplayer market prices via Scryfall.
Merieke Ri Berit doesn't untap during your untap step. {T}: Gain control of target creature for as long as you control Merieke Ri Berit. When Merieke Ri Berit leaves the battlefield or becomes untapped, destroy that creature. It can't be regenerated.