What you need:
This quest.
An alliance rogue with Glyph of Disguise.
The mob Avatar of Soggoth is an Old God located at The Master's Glaive in Darkshore, but for some reason it's flagged as a humanoid. Get the quest, use the glyph and pickpocket. It's that simple. You can still hearth and use abilities so you're able to run around cities like this. People are also able to use Potion of Illusion to copy your appearance (and you can use potions of your own to copy them after that, so with a couple of people you can stay looking like this as long as you care to keep drinking them). That way if you wanted to you could have an army of Old Gods running around the city. If you're horde you could maybe get an alliance rogue friend to do this for you then use a potion to bring it back to your own city.