Neutral, the idea is a good one... but I think that zombies and the humans are against each other so, if zombies can damage the humans the humans can damage the zombies. What I am saying is that it should be equal, so if you make it so you can't hit the zombies there should be something to protect the humans also. Or make it so that those 5 seconds the zombies cant do damage because damage can't hurt them at that moment.
With the immunity should also come 5 seconds of not being able to attack so people dont abuse that 5 seconds to create an advantage situation.
Yes! this may finally but a stop to spawn killing... But there is just one problem, If the zombie, that cannot be killed for 5 seconds, that also has speed, runs to someone and just ops them. there should also be a thing where the zombie, when first spawn does have the the immunity to get hit, but can't hit any humans for the same time...