kaalia mtg commander deck of the Vast you may put an Angel Kaalia of the Vast (Commander)

Right now, this card is selling for a price which is impressive even by the standards of other mega TCGs like Pokemon

Where it fails is that this green instant wont protect you , but rather, only your permanents

Lunar Convocation feels like a better choice today

Most Dragons have a fairly high casting cost, so discounting the mana required to cast them lets you get powerful Dragons onto the battlefield quicker

Another alternative is to use all that Mana for burn spells that have X in their casting cost

This ability has made the card into a staple in various Dredge-style decks and also a pseudo-combo piece with last year's winner Dread Return, where the Zombies from Bridge from Below give you flashback fodder to sacrifice for Dread Return