https://www.gamespot.com/articles/here-are-hearthstones-first-witchwood-expansion-ca/1100-6457344/

Today Blizzard announced its next Hearthstone expansion, the spooky haunted forest theme titled The Witchwood. And though the company has only revealed six cards so far, those six pack a lot of flavor and implications for this expansion's direction--especially thanks to the introduction of two new keywords. Let's take a closer look.

Pumpkin Peasant - This card is actually represented as a pair, because as it sits in your hand it will shift from a 2/4 minion to a 4/2 and back again. Hearthstone has certainly toyed with similar effects before, with cards like Molten Blade or Shifting Scroll changing to randomized cards from a pool of weapons or Mage spells, respectively. This represents a different type of shifting, though, because it occurs in a predictable pattern. That means you can plan several turns ahead, knowing exactly what it will be when you need to drop it. It wouldn't be surprising to see Blizzard continuing this idea with more cards that shift in your hand in a clockwork pattern.