Rogue just played Unkillable wax Rager against me on turn 3?

Sorry, I am not an expert by any means. Is this a bug or something? How can a rogue summon a 5/1 Wax rager on turn 3 with the deathrattle "resummon this minion"? Playing Standard by the way. Is the guy a hacker or something? I cant believe this is fair.