Certain app stores have been displaying a discounted version of Minecraft Pocket in order to attract buyers. However once you've paid them for the modified version, you'll find your handset suddenly has a desire to text premium rate numbers in Russia costing you many, many dollars.
It seems likely that those responsible are the owners of the line, or at least associated with those that do, so they not only get to walk away with the $3.50 that the investigative gamer has dropped on the software, but a fair amount more once those texts start flying out.
The best security measure here is to only install apps from an official source (Mojang, usually priced at $6.99). As for now, it's not clear if any of the available mobile anti-malware options would pick up on this nefarious app.
Back in the day the worst you could expect from a bit of phone malware was it changing all of your icons to penises or black boxes, but today, with bank account information and more stored on many peoples' phones, it pays to be far more secure with your downloads.