It has a very similar feel to mitosis, so that could make a good starting point.
On the one hand, it will be a fixed skill cost to spawn new creatures... on the other hand, they will have no attack or skills.
I think a cast cost of 5 or 6 for the unupgraded version is probably about right.
Then you would either keep the same skill cost and drop cast cost by 1 for upped or drop skill cost by 1 and keep same cast cost for upped.
Very nice. Pretty interesting, but it feels quite expensive and situational to be very useful.
I agree, although I think it has definite potential if the cost is dropped.
There are some strategies that can make good use of a reliable and constant stream of creatures.
On that note:
There was another card a while back that did something similar (copying creatures without retaining skills). In that case it just spawned generic creature cards. If that is not the case here, then passive traits (salvage, devourer's quanta drain, voodoo, etc.) would still get copied over since they seem to be hardwired into the card itself and can't be removed (even by lobotomize).
Along with the obvious railgun application, I could definitely see using one of these in a fallen druid or SoP deck if the cast cost is low enough. If the passive traits copy over (i.e. same card base is kept) devourers would be a very nasty combo as well.
Lastly, given that copying a voodoo doll will respam any damage or status effects (i.e. poison) it could be fun in a voodoo bow as well... Just get a handful of these in play and start popping out poisoned BB'd dolls.