13/13 stats for 7 mana, with extra six damage into enemy board per every summoned minion? Funny jokes

It’s disfunctional though. Even without speaking of that 4 HP for eight mana that means you either forfeit turn 8 or 9 by playing a useless 2/4 body - or, on turn 10, if you can use it, the effect diffuses itself. The more powerful the buff, the less the chance of it being put on something you want