Chances are they tried mixing a pet they had with another player who owns a hydra pet. According to the pet rules the wizard people are telling us, you cannot hatch a pet you cannot use.
Thus players who hatch a hydra will get a hydra they can use.
its because they probably have a grand balance and they put it in shared bank and gave it to there lower lvl balance because i did that because i am a grand balance kyle hexblood