Longtime Hearthstone players will remember the reign of the secret paladin deck. Back during The Grand Tournament add-on in 2015, Blizzard introduced a card known as Mysterious Challenger. This paladin card was not only a strong minion — a six-attack, six-health body for six mana — but it came with the bonus effect of putting one of every secret type in your deck into play.

Now, paladin secrets are notoriously cheap and not too powerful. But this was still a massive effect that ended up creating an archetype that was dominant in the game for months.

Blizzard has given Polygon a new card to reveal for the upcoming expansion set, Knights of the Frozen Throne, and if the past is anything to go by, this could end up being similarly dominant. The new card deals with mage secrets rather than paladin, and it doesn’t come with a body, but it’s still an extremely powerful effect.

Check out the video above for the card reveal as well as some of our initial thoughts on how it might be useful. If you’d like to see more cards from the new set, Blizzard has a full gallery on its official Hearthstone site.

Hearthstone: Knights of the Frozen Throne is expected to launch in mid-August. Stay tuned to Polygon for more Knights of the Frozen Throne content following the launch. You can also check out our full Hearthstone playlist on YouTube.