'Micromon' is now officially a phenomenon. It is top of the paid App Store charts on iOS and Google Play, and when you add in-app purchases to the mix? Well, it's probably one of the highest-grossing new games on Earth.
So what is it? And why is every kid on Earth apparently obsessed with it?
To put it overly simply, Micromon is Pokemon for your iPhone.
It features the same essential gameplay of collecting monsters, training them up and fighting them, and similar Japanese-style graphics but even more colourful and exotic.
It's addictive and obsessive, encouraging players to pour in hours of time and effort to build up their cadre of warriors, and then battle them online until they faint in really cute, non-threatening ways.
It's also -- as we mentioned -- totally unoriginal. In fact the only reason it's managed to find such a huge audience so quickly is simply that Pokemon didn't get there first. As one of the most popular mobile games ever Pokemon is an obvious candidate for an iPhone cash-cow. But Nintendo's policy on smartphone games is simple: nope. And so the space was clear for a new competitor.
How does it play? Check out our guide, above.