Ikran's Comments

The rare quality version of this is a colour-changer, meaning it will change between different colours every time you summon it.

These seem to be changing colour every time you summon them. So far mine has appeared with all the colours except the white one with blue spots.

I don't know if this is just the rare quality ones that does it, might be, since my poor quality one never seems to change colour.

Yes these can be found in Mount Hyjal, levels ranging from 22 to 23. They only seem to be found as secondary pets in battles, but are not that rare to get.