We've introduced a new feature into the beta wardrobe called skins today! Basically, if you have a zombie or morostide zapper base, you can claim them in the beta wardrobe and use them any time!
That means you can have a human avatar, and switch back to being a zombie to pop into the zombie den, you can absolutely do that.
We will be able to add skins as prizes to achievements and events in the future, so keep a look out for fun new ways to change your avatar!
I really wish this had been done while the Morostide zapper was still active, but it'll be interesting to see how skins may be used now :D