Turn yourself into a walking corpse. You immediately lose control of your actions, and are aggressive to humanoids and beasts. Upon you biting any living humanoid or beast, they are also turn into a zombie. However, their zombification is permanent. Zombies, aberrations,  celestials, dragons, fey, constructs, and the like will not be aggressive to you. Biting another zombie does nothing, but it doesn't matter anyway because you aren't aggressive against other zombies. Your walk speed is drastically reduced by %75. Your Strength and Constitution are both increased by 5 each. Your Dexterity is immediately lowered to zero, and you can't use weapons. The only three things that turn you back to a humanoid are waiting for the spell to end, someone casting a spell to make you a humanoid again, or someone using a Phoenix Down on you.