Nano-bot Zac or liquid metal zac
I'm not a fan of zac at all, but since he has so few skins I figure maybe he gets a robot skin as well. Since he's just a blob I figure he can be a made of millions of nanobots that act like a liquid.
Or be made out of that liquid metal like the bad guy from terminator.
Both are cool and since he has so few skins why not.