Pippa, Duchess of Dice is a rare Legendary Creature — Human Noble card from Unsanctioned (UND), collector number 68. Current market price: $0.20, TCGplayer market prices via Scryfall.
{2}{G}, {T}: Roll a six-sided die. It becomes a green Die creature token with power and toughness each equal to its result. {2}{U}, {T}: Reroll any die. (Activate only any time it makes sense.)