Dawnsparks is an epic frostling unit that generates mana when it attacks. The strength of Dawnsparks and the amount of mana gained can be increased when upgraded. Dawnsparks sees play in ramp and control decks.
Dawnsparks can give you a lot of mana on the next turn, but it needs to survive until then.
Potentially, played on turn 6, Dawnsparks will give you at least 11 mana the next turn, which can be used to play more powerful units than your opponent, which Winter Pact has a lot of.
Since Dawnsparks has to attack a unit or structure to gain the mana, you need to make sure there is an enemy for it to attack. You can do this by placing Dawnsparks 2 tiles ahead of an enemy unit, or placing it in front and freezing the enemy.