It counters target spell unless its controller pays and it creates a 2/2 black Zombie creature token with decayed
If you can get Haakon into your hand, which you can do with cards like Netherborn Altar and Command Beacon, he becomes an incredibly grindy value engine for a Knight deck, letting you replay your fallen allies from your Graveyard
Because Dralnu gives flashback to instants and sorceries, you can also use cards like Legerdemain and Switcheroo, and then cast them again when you inevitably get Dralnu back
You pay the cost by using resources or Don, depending on the specific mechanics of the game
Frequently Asked Questions (FAQ) Check the color of the set symbol on the right side of the card (Black=Common, Silver=Uncommon, Gold=Rare, Orange=Mythic Rare) or the letter code (C, U, R, M) at the bottom-left of modern cards
Also 130 hp for a stage 2 is good, and a two colorless energy retreat cost is also not too extreme