I recently hatched a male Vulynx with the mutation 2 of Flower Adornment however neither of his parents have this mutation(neither visible nor carried). How is this possible? Do some pets have hidden genes? Or do some mutations just occur randomly?
Here is the Vulynx if you want to take a look:
https://www.sylestia.com/view/pets/?petid=3312511

Some of his great ancestors or someone in his bloodline may have had those traits as well, so it's possible.

To expand on Shayni's answer - it's very common for a pet to have a hidden trait! These traits are carried underneath a visible trait - so it's like having 2 traits in one slot.

If a pet is genetically tested, there are a couple ways to see hidden traits. The first is on the advanced search - if a trait is written in purple font like this:

That means there are hidden traits under the pet's visibles! The letters (DI) and (BK) tell you what traits they are - in Lacey's case, Mutation 2 (B) is her visible Jeweled Collar, and (K) is Ethereal Armor.

Your pet's father has lots of hidden traits:

His mutation 2 is (BI) - (B) for Jeweled Collar again, and (I) for Flower Adornment! So that's where that came from.

When pets with 2 hiddens are bred together, there is a 25% chance for the dominant hidden trait to become visible. So since (I) was dominant to (K), he got his father's hidden trait as visible!

If you were to have him genetically tested, you would be able to see that he actually has his mother's hidden trait underneath his visible as well - so his mutation 2 would be (IK)!

It can be a little complicated - but to put it simply, no traits just randomly appear. They're either carried, visible, or hidden underneath ^-^ Genetic testing is necessary to see what the hiddens are, but they can be passed down by breeding even if you can't see them.

Feel free to ask if you have any questions about this! I know it can be a little confusing at first!

Thank you very much that was very helpful Where can I get genetic testing kit if I don't want to use diamonds?

Unfortunately, the only way to get an exceptional (unlimited) tester is to use diamonds in the Diamond Shop.

However, there are lots of people who offer to test other players' pets for free! You can find them in the Breeding Discussions forum! If you have any you want tested right now, I would be happy to test some for you. You can also ask in region chat!

If you want an exceptional tester and don't have real money to spend on diamonds, you can always buy diamonds with gold on the Currency Exchange.