Super Tiny Transformation For Healers/Pets/Minons, Even Works In Arena (Patreon)

In Ahn'Kanet, the Old Kingdom, part of the Azjol'Nerub complex, in Dragonblight, Northrend there is a boss that almost qualifies as a secret of the game since few newer players will have ever encountered it. Amanitar is an optional side-boss in the heroic version of the instance that LFD groups never kill. Amanitar has a very interesting ability called "shrink" which activates 10-15 seconds after aggroing the boss.

The ability shrinks the target to 1/3 of their normal size. This is a debuff, and it causes serious issues for dps since it reduces their damage by 75%. However, the ability has an interesting effect. It has no duration-it is only cancelled when the player consumes a healthy mushroom in the vicinity of the boss, or kills the boss. If you port out of the instance (you can use a hearthstone, it may take a few tries as Amanitar's attacks may interrupt the cast) the debuff will persist indefinitely until you die.

For dps classes the cost in damage reduction is obviously not a good trade-off. Tanks have no real reason to be small. Healers however do not need damage* and benefit from being harder to target and locate. Moreover, because this is a debuff it can be used in arena. Trying this with a mistweaver monk I began to understand very quickly why Blizzard don't allow shrinking normally in arena-it is really difficult to kill a monk that tiny. Be warned this is incredibly annoying from your opponent's perspective so it could generate reports: that said it did not generate the type of response from players I've received when using a more obvious exploit-probably most players are unclear on the exact mechanics of shrinking and transformations in arena. 

Outside of pvp, Amanitar can also be used to shrink your permanent pets/minions for cosmetic purposes. For some reason the debuff damage reduction does not seem to affect pets at all, so you can have your own permanently tiny pet indefinitely. Hunters/warlocks can put the debuff on each pet they have. (If you aren't interested in this type of silliness bear in mind you can actually sell this sort of trick to people who like cosmetic effects for quite a lot of gold. Just walking around with the dimunitive pet is quite a good advert, you will get whispers). 

* I'm aware there are situations in high-end pvp where healer dps might be important. These situations are not typically encountered by normal players however.