The Lucky Button play online

So, if you click the lucky button, that means you don't click the unlucky button.
You get a random legendary of your choice, so for example you can get The Lich King, being a 8 mana 8/8 minion with taunt and at the end of your turn add a random Death Knight card to your hand (I don't really know why it says deathknight card because deathknight cards are the deathkinght heroes like scourgelord garrosh, valeera the haoloo and so on).