Johnny, Secret Santa

{s}{s}{s}Secret—(From your hand, you can put this card secretly underneath any card. Once per turn; you may move it to another card. If it get's noticed by an opponent, at the beginning of your next upkeep; you have to pay it's secret cost. If you can't, you lose the game.)
When this card is noticed, each card it was underneath becomes snow and gains: "{t}Add one snow mana of any color."