How do you change your pet's species or color?

Are the labs just totally random?

Is there like a morphing potion?

Is there a guide on this?

If you'd checked out the "Useful Help Threads" sticky, you would've seen a link to an FAQ. Scroll down for info on pets.

While you're going to get people who will give you the answer directly, I firmly believe in figuratively teaching people to fish rather than merely giving them a fish. Hopefully any future questions you may have can be answered instantly by the FAQ. :)

There are a large number of really inexpensive elixirs at the moment that will change both your pet's species and color. It's not difficult at all to do here as it can be on other sites. :)