Hearthpwn

Almost (almost) seems like reverse power creep for Mad Scientist. I guess deathrattle ==> battlecry can be important, but not always worth the 1 more cost.

Would be surprised if this card don't see play in wild secret mage

The wording is interesting on this on. Compared to Mad Scientist which puts a secret, this one casts it. Does it trigger effects that happen when you cast a spell? Can it get countered by a mage's Counterspell?

It works just as Mad Scientist, the wording in Hearthstone is just too inconsistent 

The best candidate to play this is of course mage, since her secrets are the most expensive. Maybe hunter as well, in combination with Mystery Winner you can get a very annoying board. Not good in paladin and probably not good in rogue, since the new secret of rogue kinda sucks

rogue already has a decent secret package, but synergy with secrets are kinda low, only Hanar and stunner

hunter has hyena and new spell that summons extra beasts per secret

mage in standard has prince, new legendary, flak and 4 mana 8/8

this card is way better in mage and hunter for sure