It was a reward for something and ki gave them out to wizards a year or something ago. They do not give more pet storm beetles, but they might give rain beetles. I have a storm beetle if you want to hatch. However, they do not give the best talents. But you can train them so they have awesome talents! Madison Winterhorn realm sunbird on a hydra.
The W101central page doesn't say a couple of things: First is that although it hints at it, it doesn't say it straight out, you can't buy it, get it as a drop, or as a prize, etc.. right now (as far as I know). Second is that you can not hatch this pet. So if you find someone with this pet and hatch you will only get your pet back. (If I'm wrong I'm sure many will correct me, but this was true a few years ago when I was trying to get one) Third, is that you CAN get the rain beetle which looks just like the storm beetle but in blue and yellow instead of purple and yellow and also gives the same storm beetle spell (the babydactyl also give that spell). But you may already know that and really want the purple version like I did.