If you're a Star Wars fan, then this Hearthstone Tavern Brawl will certainly remember you something! In "When Clones Attack", each minion you summon will also split into a 1/1 version. You only need to choose a class, and the game will give you a random deck.
With this cloning mechanic, the Battlecries won't be played twice, but the Deathrattle will.
Slight detail you need to know: if you put a minion with Magnetism and merge it directly with a Mech, it will still split — even if it never "really" arrived on the board.
The clone version won't merge but will rather be placed on the right side of your original minion. Like every week, your first win will reward you with a classic card booster.