Earth. A large round(ish) floating blob of stuff inhabited by a primitive species called humans, capable of very little in the grand scale of things.
Of course, humans aren’t the most important species on the planet, although many of them believe this to be the case.
The planet was originally created so that the pan-dimensional beings that take the form of little white laboratory mice could run their experiments in the search for the ultimate question of Life, the Universe and Everything.
Slartibartfast’s award-winning Norway is particularly interesting, with all those lovely crinkly edges made up by the fjords.
Thankfully however they seem improbable of ever discovering warp travel and so can safely be deemed mostly harmless…Mostly.