So this card is a bit of Barnes and a bit of Shadow Essence. It hints this might be a very annoying card if someone makes it work.
I wonder does Shudderwock wants to play it? Not sure about it. Would you like it to change to random minion from your deck? Would it stop casting like nerfed Yogg-Saron, Hope's End I think it is anti-synergy.
This is a very different kind of Shaman. Something we haven't really seen yet. Ancestor's Call and Eureka never really worked. This gives you a good way to play those things.
In standard, there isn't a bunch of stuff that I can think of that you want to "cheat" out with this.
Maly (obviously) - could make for a really interesting Aggro and/or Combo deck. Hakkar? (which is actually something I've wanted to try in Shaman for a bit.) Turning this into a 4/4 Spirit of the Frog is pretty cute if you're going to go the Maly type of route.
The window for this card is wide open. I think it can be a lot of fun.
I feel uncomfortable knowing that someone is stalking me behind a corner.
The effect is weird (in a good way). For now I'm thinking of Deathrattle shaman in wild or Malygos, if you build your deck in a very specific way. I like how cards like this open many deck-building possibilities.
Not sure about this one. I guess it will need a very specific deck built around it, and I don't quite see how that would work. But I'm sure somebody smarter than me will at least come up with a solid meme deck for the morpher.