Vi'larion, the Inevitable

Flash, Flying, Ward - {u} or Pay 2 life.
Whenever Vi'larion attacks, add X blue mana,
where X is the total power of attacking creatures.
Spend this mana only to cast spells. Until end
of turn, you don't lose this mana as steps and
phases end.
When Vi'larion dies, return it to its owner's hand
at the beginning of the next end step.