Hearthpwn

Damn, this card sucks so much that even when your opponent plays Servant of Yogg-Saron and its battlecry casts this, it doesnt give u the mana crystal, if it didnt buff a demon first, hahaha, wording at its finest :P

Oh thanks I needed 1 mana to smorc you with leeroy next turn

Well, that makes it great at climbing from rank 1 to 20 quite fast. :)

Fun card.
Early game you can scare your opponent, late game there is no down side.

Yesterday I was fighting a priest. I kept Demonfuse in my hand and he used Mind Vision :)

Demonfuse can not be used against you like Demonfire and Demonheart (both state 'friendly' Demon).

Anyway, later in this game the priest did cast Demonfuse and also Shadow Word: Death so he found a way :)

The difference is, those are unusable for you, while this is unusable only for your opponent. 2 mana +3/+3 is totally nuts and very relevant even in mid-late game, while the drawback only matters when played in early game.

I'm not saying that this is a good card though, just that your point is inaccurate. The drawback is pretty big in the early game.

Are you pensaer's son?

Quote from YggorHS >>

Are you pensaer's son?

this card is actually really good 

if you get turn one flame imp and turn 2 this card you just win the game 

It is even better when you opponent plays a turn 3 Polymorph. That is the best part.

apparently you can draw Demonfuse via Sense Demons

i think this card is going to shine the most when tgt is out 

lol did u say smth?

Surprise! It sucks!

In a world where Demonfire is not used,I can't see how this card should work. Maybe i'm wrong...

You were not wrong.

"This cannot buff Lord Jaraxxus the Hero"

i woudldn't play this all day :) and how come Sacrificial Pact which says " destory a demon" works on lord jaraxxus , while this card's +3/+3 doesn't work?

Sacrificial Pact's interaction with Lord Jaraxxus is causing confusion in that way; the devs are considering removing the Sacrificial Pact interaction for the sake of consistency. Source

Please, check your facts, thanks.