Seen this idea quite a bit before. Here's why it doesn't work:
1) Strictly better than Parrallel Universe.
2) Instant kill with Immolation (you get quanta back too, just in a different element)
3) 1-for-2 card advantage - you're basically getting a free instant creature kill (which this game can actually be quite picky with) and a creature. Making it a creature would've just broke the thing in two.
Not that I want to buzzkill your card, but this idea has run the gauntlet before and the above reasons are some of the more notable reasons it got rejected by the community. Do you have any ideas on how you'd deal with what I've listed above besides raising cost?
No worries. I suspected it has been proposed several times, but one version might just be that much better than the others that it will work
Solution attempts
1: Make it backfire - Slaver has a 30% chance, Slave master a 25% chance to take one of your creatures and give it to the opponent
2: Not much can be done about it, except for raising the cost a bit (8 or 9 perhaps) to make it an ineffective use
(To be fair, the same argument can be made against TU, Mito, and even Afla, if used on your own creature)
3: While not exactly negated, the advantage could be lessened by delaying the effect. For example removes the creature from play in the first turn, and adds it to your field in the next
The other option that came to mind is that instead of the direct transfer, remove the creature and add it to your hand - but that would probably make it useless
