One of his more recent games, "Obby Creator," earns him up to $20,000 a month. Jacob Girdler joined Roblox in 2011 on a whim. "I was just sitting there watching TV with a friend, when he said ...

In a blog post, Cavanagh announced the "obby," which is Roblox shorthand for "obstacle course" (or just a platformer) and a popular genre to make among first-time creators on Roblox. "For the past ...