User blog comment:NeonSpotlight/NeonSpotlight's anniversary AMA/@comment-27859592-20170101022718/@comment-3391671-20170101195004

Sandboxes are made from normal pages, not blog pages, Clay. As for names, as long as it is appropriate, both by common sense (such as avoiding foul language) and by the policies on the wikia (no random letters: "apimefvqskjan"), any title is fine for the sandbox. "Sandbox" doesn't necessarily have to be part of the title, actually.

By having that setup of "User:XXX/Sandbox", it not only becomes a page on the wikia but also a page personally attached to your user page (which is why under the page title, it'll have "go back to User:XXX"). It's a public page, but hopefully people will understand that it is a more personal public page designated to a given user.