Coestar narrates his adventures for fans who watch him play for entertainment or to pick up tips, sprinkling in some language that might not be suitable for younger followers.
And that's enough for Mitchell Brown and Scotty Vrablik, American students in the Hong Kong equivalent of Form One, to reject that video from their own fledgling website.
A growing number of teachers have embraced as an educational tool, but are looking for "clean" versions.
" is a totally, open-ended sandbox," which makes it easy to customise for use in the classroom, says Joel Levin, co-founder of TeacherGaming. His company created MinecraftEdu, a modified version of the game for classroom use.
not only engages students, he says, but encourages skills such as resilience, problem-solving and thinking outside the box.