It's 1 mana cheaper Chillwind Yeti but with huge downside. IMO it should have rush or cost 1 mana less to be really good, now it's just OK. Probably not good enough for Zoo (seems slow), but might fit into midrange with Diseased Vulture.
Really good since this is just a solid card for zoo and really good in a suicide/painlock mostly cause it can trigger its effect more than the turn it’s played, so you can play this on 3 and curve out a Diseased Vulture or coin this on 2 and curve out a Duskbat or something similar so this is quite nice given the downside is an upside really for warlock
As others have pointed out, this into Diseased Vulture is a very good curve. Now the scary thing about this that Neferset Thrasher WILL stick because its very hard to remove it at that stage of the game.
Im not sure if painlock needs heal, it just wants to reduce the opponents health faster than its own.
Unlike many of self-damaging Warlock cards, this one pays life after it attacks which is a huge difference. Plus it is perfect on turn 3 followed by Diseased Vulture, which can summon you another copy. You can always sacrifice it with Grim Rally or EVIL Genius after "it served its purpose" (pun intended) or evolve it with the lackey.