Vs. Everybody A few days ago at the annual Osheaga Music Festival in Montreal, the artist formerly known as Mos Def, called out the entire rap game for a battle. Enlisting Black Thought and King Los, he says the triumvirate are accepting all challengers. No Joke. Speaking of which, Yasiin is also trying his hand at comedy. Peep the clip below. UPDATE: Lupe Fiasco accepts the call.