Granted, but it comes at a high price. You cannot be hurt because you are covered in 5-inch-long spikes all over you. You will never have physical contact with another human being ever again. I wish I had a pet zombie.
Granted but you also acquire the ability, and you become able to pass through more than walls, you pass through everything! So, you fall to the center of the Earth, and get stuck there...
I wish that Minecraft would send out an update already!