This is the Swashburgler HS Rogue Card being released with the adventure One Night in Karazhan. It’s a Pirate and has the text: Battlecry: Add a random class card to your hand (from your opponent’s class).
Pirate decks have never quite cut it in Rogue but the addition of this card strengthens the decks a little.
It’s always nice to have one of your opponent’s class cards, you often get something good, and the extra card is a bonus too. This is a neat little 1-drop, and even if you draw it late the Battlecry means it’s not a complete waste of mana.