It's pretty garbage IMO for standard. Best used against decks with very few minions that are combo heavy, kinda like a dirty rat++.
Mainly garbage because it costs 7 mana...that is your entire turn essentially, and this card takes up a late game slot or ramps the curve of your deck signifcantly. maybe it will see some use in Wild with shudderwock or brann or something but I doubt it.
In Wild, it would only cost 1 Mana with that one murloc out. Also, in Priest, they can discount cards in hand like crazy. And Warlock can play deck of chaos and it becomes a 4 Mana 7/4. And in DH, it can be reduced to 4 Mana with Skull, then duplicated with Zai, the Incredible.
It's a bit expensive, but control decks could use it to win control mirrors (R.I.P. C'Thun, the Shattered). Also meme Rogue decks can use it with Tenwu and Shadowstep on Tenwu to get rid of the opponent's full hand (kind of the inverse of a mill deck;)
As much as I like the idea behind the card, it's not going to see any play in standard. It's only useful against 2 decks right now, Tickatus warlock and OTK DH. Maybe there's an argument to be had with it vs rogue but I doubt it.
The meta is just too fast and the card too slow and unreliable for Mutanus to be any good. So, unless there's some kind of combo that it itself can bring to the table, it just won't see play.
Historically, 7+ mana cards that don't do anything to the board immediately have been tough to play, but maybe it will find a way.
I like it, anyway.
Yeah, I see it as as a tech cards control decks can use vs combo decks. The problem is the cost. It is probably too slow for wild, and useless vs aggro. The only plus side is that it doesn't leave any resurrection options available.