While the tooltip for the potion simply states that it will transform the imbiber to look like someone else, it's far more complicated than that. The potion will actually transform you to look like whoever you happen to be standing closest to. And it's that delightful little fact that has turned waiting for raid time to start into a game of let's see what the Potion of Illusion is capable of, with entertaining results.
The legendary staff Dragonwrath, Tarecgosa's Rest isn't just an amazing staff -- it'll also turn wielders into their own flying mount version of Tarecgosa. And if you happen to use a Potion of Illusion while standing next to a Dragonwrath wielder in their flying form, you'll turn into Tarecgosa, too.
You won't be able to fly; that's reserved for those that have the legendary staff, of course. But you can perform all of your normal combat moves as an obnoxious, huge, screeching, stabbing, casting dragon. And even though you can't fly, you can jump. Have you ever seen what it looks like when a grounded dragon hops around, trying to take to the air? It's hysterically funny.
The best thing about Potions of Illusion is that the effect can be chained through a group of people -- so someone can use the potion to take dragon form, and anyone standing next to the transformed person can use a potion to also assume dragon form. If the effect wears off, just stand next to someone else with the potion and change again.
While some report that using a Potion of Illusion next to someone using a Lifegiving Seed transforms you into a herb that wanders around and can attack people, I didn't find this the case when I tried it. However, the effects were still cool, as I turned into several different random characters, both Alliance and Horde, as a result -- characters with unique and cool skins and clothing, like the Grimtotem skin pictured above.
Whether this is a result of using the potion while standing atop an herb or simply sheer randomness from the potion itself, I don't know. I do know that I've turned into a draenei with a ridiculous mustache, the Grimtotem tauren pictured above, a random orc in shaman starting gear, and a female gnome in a fetching dress that didn't look like any model I'd seen before. It may not have been an herb that could attack things -- but it was fun, all the same!
If you happen to have a Brazier of Dancing Flames, you're aware of its effects -- dancing with the brazier will transform you into a stationary dancing flame draenei. However, if you use a Potion of Illusion while standing next to the stationary dancing draenei, you'll turn into a flame draenei that is neither dancing nor stationary. You can run around, you can perform attacks -- and heck, I guess you can dance if you want to, but why would you when you're free to do whatever you want?
The flame draenei skin is so flashy that it immediately draws attention when you're wearing it, especially if you happen to be hopping around, running in circles, casting, and other things that flame draenei shouldn't be capable of doing. And if the person who decided to dance with the brazier wants to move around too, all they have to do is stop dancing, stand next to one of the roaming flame draenei and pop a potion of their own.
This one is a little more obscure, mostly because it involves items that are no longer obtainable in game. If, however, you were lucky enough to get your hands on Arlokk's Grasp and Thekal's Grasp from the original version of Zul'Gurub, or you know someone that has a pair, this is entirely possible. While using both weapons, you have a chance to proc Primal Blessing, which turns you from yourself into a giant, walking tiger aspect.
So here's what you do -- duel a player, and simply auto-attack. Wait for the proc. Once the proc transformation occurs, have your dueling partner pop a Potion of Illusion, and they'll turn into the tiger. When your Primal Blessing wears off, use a potion while standing next to them, and you can be a tiger as well -- only this time, the effect won't wear off until the potion does. Invite your friends, turn into a bunch of tigers, and go confuse people! This works with pretty much any transformation proc, so if you happen to have a Deathbringer's Will in your possession, you can try it with that as well.
If you're looking to really confuse people, look no further than the Stranglethorn Fishing Tourney, where you can get your hands on the magical Hook of the Master Angler. This amazing item will turn you into a fish, allowing you to breathe underwater and swim faster. Sounds great, right? Well, the trinket can only be used underwater -- once you hop out, you turn back into your normal self. Unless, of course, you have a friend with a Potion of Illusion.
If they use their potion while swimming next to you, they'll turn into a fish as well -- but unlike you, they can swim right up out of the water and onto dry land. Once you're out of the water, use a potion while standing next to them to nab the buff for yourself, and delight in your new surprisingly mobile fish form. Using attacks while in fish form will display your weapon in the fish's flippers.
Before you dismiss this, I want you to picture a very bored day in your guild. Someone suggests attacking the opposite faction's capital city. Now imagine if you will, tooling about in Stormwind or Orgrimmar only to encounter a raid of dozens of very angry flagged fish rampaging through the streets.
These are just a few things you can do with the wondrous Potion of Illusion. There are all kinds of other things this handy little gem can do. I'm sure, given enough time, my guild will eventually find them all -- after all, we've got a lot of free time on our hands and a zest for finding bizarre things to fill it. Though the Potion of Illusion isn't really spoken of very often, it's one of the better things to come out of Cataclysm -- and I'm hoping Mists offers us something just as unusual and fun.