Pokey, the Scallywagg - Mystery Booster 2

Menace

If you would flip a coin, you may instead roll a d20. 1-10 is tails and 11-20 is heads. (It counts as rolling a die, not flipping a coin.)

If you would roll a d20, you may instead flip a coin. Tails is 1 and heads is 20. (It counts as flipping a coin, not rolling a die.)