The cobra you are talking about may be two things:
One is the wind snake, which is LR’s combat pet. This is not recommended as it has no practical value
Another possibility is that it is a pet snake. This is an ordinary ornamental pet that anyone can bring. It looks like a small snake on the ground. It cannot attack or be attacked. It can be found in Orgrimmar, the main city of the orcs. Purchase from Snake Merchant