For the reasons I explained above, I prefer the original (spell) version. What if it was: "Target a non-undead creature. The creature's skill is now : Zombify. Kills the creature if not activated."
What if the zombie skill was: Bite: infect target for 2. Upon death creature turns into a zombieSimilar to aflatoxin but instead of malignant cells it turns creatures into zombies. Fits with zombie theme of infection and warrants the lobotomy since the creature has to die first.