Hearthpwn

This can backfire SOOOO badly.

This is a scary card with a lot of mid-game/late game potential in control decks. It should see one or even two copies being played in most control decks.

In general, this card is good at denying value from battlecry minions (e.g. Elise/Golden Monkey, N'zoth, Justicar, Book Wyrm, Reno, Twilight Drake, Jeweled Scarab, Ivory Knight, Azure Drake, Kazakus, enemy Rat). It can pull out doomsayers that the opponent doesn't want to play, and get a guaranteed board clear on the opponent's turn.

Against aggro: This is a 2 mana 2/6 taunt if they're in topdeck mode or if their board is full. It could be a gamble in the early game.

Against ANY deck in the mid-late game: It makes your board clears more powerful.
Scenario 1: Rat+Pyro+equality, killing an additional threat they've been holding back (like thunderbluff valiant, Rag, Syl, Maly, Arcane Giant)
Scenario 2: Rat+brawl, getting guaranteed value from your brawl. You don't have to brawl if you don't pull an enemy minion
Scenario 3: Hallazeal+rat+eleD/lightning storm: additional healing, and the rat survives the AOE.
Scenario 4: Rat+Dragonfire potion, leaving the rat alive

Against control: Once you've figured out what deck your opponent is playing, you have guesses on what they're holding, and the way they're trying to bait removal. You can try to force pull their win conditions and deal with them. 
Rat+entomb, Rat+Syl+Shieldslam (or some other spot removal), Rat+hex

That Big-Time Racketeer synergy...

Opponent plays Astral Communion

Plays 2x Dirty Rat

Holy hell this is gonna buff Silvermoon Portal and Piloted Shredder (In wild) so much!!!! :O

does this work like Ancestor's call or summons a copy of the card? The wording is not spevific enough (cos of the space) and similar cards say "Put", not "summon".

It will be like Ancestor's Call, your opponent will no longer have that minion in their hand.

Good against aggro? 2/6 taunt for 2 mana, the opponent typically only gets a 1 or 2 drop from this battlecry...? Hmm, dunno. Yeah, dunno. Interesting idea for sure, either way, but it's hard to tell how this card will fare once the expansion is out.

Getting this from Evolve or Master of Evolution from a 1 drop is also an interesting prospect, though an unlikely one.

May also be interesting before Brawl to kill an extra minion of the opponent's while also having a better chance that one of your own minions survive?

That moment when you decide to keep Deathwing in your starting hand...

Time to keep Ragnaros in my starting hand against Priest

deathlord 2 electric boogaloo

Counter to fatigue warrior. Get their Justicar and Acolytes out of their hands. Kappa

This is a spooky card, to say the least. It is a control 2-drop that can win or lose games by itself.

The amount of bad starting hands I've had in control decks indicates that this card might very well pull out something you can't chew through right away, if you are YOLO enough to drop it without knowing what kind of deck you are facing.

It can also neutralize N'Zoths, C'Thuns, Yogg-Sarons, Cabal Shadow Priests, Golden Monkeys, Renos, Justicars, Loathebs and Mysterious Challengers, but it requires a lot of luck to do it, unless your opponent only has one card in their hand.

Other times, it can pull out a Doomguard, a Darkshire Councilman, a Ragnaros, a Highmane, or a Shredder.

Usually, it will probably pull out an Argent Squire, or another small minion on turn 2, and soak some damage, at least if the meta is as fast as it is now. If it becomes slower, this card isn't gonna be very useful in your starting hand, because a turn 2 Ysera ruins your whole day.

yeah that's why this is a tech card when aggro's flooding the meta

Quote from amirosamir >>

the card says summon so maybe it trigger battelcries :/

 

interesting card but probably too risky to play maybe in control warrior with brawl

It does not remove from the hand.

From hearthstone gamepedia: 

Put into battlefield effects are abilities which puts cards from the player's deck or hand directly into the battlefield. They may affect minions or spells, and may require a specific type or sub-type of card.

Cards put into the battlefield are not directly played from the hand (even if they are put into the battlefield from the hand), and as such do not trigger minion Battlecries.

Put into battlefield effects are distinguished from Summon effects, which summon entirely new minions without consuming existing cards; and from put into hand and card draw effects, which place cards into the player's hand, rather than directly into play.

This is from HearthPwn's exclusive reveal article:

Dirty Rat is great at preventing Battlecry effects which means Kazakus, leader of The Kabal, is going to cry.

Why would Kazakus cry if he still remained in the opponent's hand? Blizzard has changed their wording before to save space. An example would be Reno Jackson and Kazakus. Although they are worded differently, they still trigger when the player doesn't have any duplicates in their deck. If Blizzard wanted Dirty Rat to not remove the minion from the opponent's hand, then they would have used the word "copy" in the card text.

Pyro+equality is usually more than 2 for 2, so it's 4 for more than 4. It's a bigger board clear that could include a Rag or a Syl for your brann or rat