If the target is not legal as Flick a Coin tries to resolve, Flick a Coin is removed from the stack. You won't create a Treasure token, and you won't draw a card.
Flick a Coin deals 1 damage to any target. You create a Treasure token. (It's an artifact with ", Sacrifice this token: Add one mana of any color.")
, Sacrifice this token: Add one mana of any color.")
