Dragon's Fire Requires a Dragon To Cast
You can't cast it unless you have a Dragon to reveal, or a Dragon on the battlefield. You can't cast it to deal 3 to a target.
Same here, cost me two games in a row
Experiencing this same issue. Oracle text: "As an additional cost to cast this spell, you may reveal a Dragon card from your hand or choose a Dragon you control." as of now it only allows you to cast the card with additional costs and not without.