So I wanted to put this one here because, while not an official custom, you CAN custom/make your own Zombie colored toy.
What I noticed from the drop was there were
two specific colors always factored in;
meat, a two color marble or
an unspecified marble of purple and green.
Take the above Apollo and Pearce for example. Their "Natural" color is a Grey with a tan base (Apollo) and Hickory (Pearce). With the Zombie colors,
one of these marbles was mixed in with the natural or signature.
Below; Scorn in his Sig with meat marbled in.
Xar in his Natural with the purple and green mix, and then an Apollo in his natural mixed with meat.
Nova in his Sig + meat
Dragon Tongue in Blue Skink; the tongue part faded normally but the base had the dark blue muzzle
with the green and purple also marbled in.
Kelvin in his Natural + the green n purple. Note how his blue in the natural gets muddled. This happens because the blue used in his natural is translucent.
Some color blends were exceptions however
Such as this Chance; it looks like the shaft was meat + black from his Sig, but the base also is marbled unlike his sig.
Not all of the toys dropped were perfect and I had seen a few like Chance, but overall the bulk of this dropped had these consistent blends