Miro's trinket

When Miro's trinket enters the battlefield,
choose an opponent.
{1}, {t}: You may look at and play top card of the
chosen player's library until the end of the turn.
You may spend mana as though it were mana of
any color to cast those spells. If you don't play a
card from the chosen player library this turn,
Miro's trinket deals 2 damage to you. You may
only play one card a turn with this ability.
Activate only as a sorcery.