Pets/Minions/Forms For All Specs In A Class (Patreon)

EDIT: There are some interesting residual effects from this exploit but you can no longer summon multiple minions.

Patreon Aetherian kindly contributed this to me:

Just found if I enter a Torg run as frost, immediately swap to unholy and summon pet, then do a floor (not sure if necessary) then log out, when I log back in I'm back in frost with a permanent (named) ghoul. Likely little use but you'd know better than I :D

(It is not necessary to clear the floor, you just need to enter Torghast,switch spec, log-out, then leave)

I tested this with a mage and was able to do the same thing by switching from fire to frost and summoning a water elemental giving me a permanent* pet as fire. 

I noticed also that various buffs that were specific to arcane could be glitched in the same way to appear for fire and frost. This was not useful in itself but it is possible to do other things such as obtain boomkin form in resto specialization, or shadow form for holy priests. 

There are a lot of permutations here: members are encouraged to experiment. 

It appears that there are no restrictions on the pet's use, even arena or mythic+ dungeons (it is relatively unusual for any kind of exploit to work with these). 

*The off-spec pet does not survive player or pet death. 

Pets generally contribute a significant amount of dps and utility, the main difficulty is keeping them or the player alive long enough for this to be meaningful.

EDIT: this does not work with most or even many passives. There has to be a visible buff, other verifiable effects are limited to the aforementioned pets/minions and class-specific forms.