Pokemon Go, the wildly successful mobile game, has been downloaded around 800 million times and scooped over $2bn (£1.5bn) in revenue since 2016.
Figures like that were always going to spawn some imitators.
But the latest - the Catholic Church (followers: 1.2 billion) - might come as a surprise to many.
"Follow JC Go!", a Christian take on the game, lets players "catch" saints or Bible characters, instead of the little Japanese monsters.
The game is the brainchild of Fundación Ramón Pané, a Catholic evangelical group, which made it in preparation for World Youth Day 2019, a Catholic youth event taking place in Panama in January.
As with Pokemon Go, the game uses the player's smartphone camera to take in their surroundings, then superimposes digital characters. But you're more likely to find Saint Peter than Pikachu.
Players progress through the game by answering religious quiz questions when they "meet" a saint - like attributing a quote from the Bible. So Moses might ask the player, "Was it me who said: 'My God, my God, why have your forsaken me?" If they get it right, the character will join their e-team (or Evangelisation Team).
Players can also collect virtual water, food and "spirituality" to contribute to their in-game health.
The game encourages real-world worship by prompting the user to stop and pray if they pass a church. Or in a hospital, they might be urged to say a prayer for the sick. Players can also donate to charity through the app.
Follow JC Go! launched in Spanish on 19 October, and Italian, English and Portuguese versions are expected in the coming weeks. Its creators say the goal is to teach players of all ages about the Catholic faith.
Though the app wasn't made by the Vatican high command, the Pope is alleged to be a fan.
"You know, Francis is not a very technological person, but he was in awe, he understood the idea, what we were trying to do: combine technology with evangelization," Ricardo Grzona, executive director of Fundación Ramón Pané, told Catholic news site Crux Now.
The site reports that 43 designers, theologians, Bible experts, and Church historians have poured 32,000 work hours into the app since August 2016. It was reportedly financed with $500,000 of sponsorship and private donations.
On the Google store, early Android phone users have given the app a less-than-heavenly 3.2 stars out of five.
One reviewer, JR SV, commented: "The best app I have on the phone, I feel happy to follow the path of the Lord from my smartphone."
Another (perhaps less seriously), gave it one star, mourning: "I wanted to burn heretics, but it wasn't possible."