[Sans snorts in amusement, leaning back again.]

You'd be surprise at how infrequently people actually ask that.

[They ask him what he is a lot, sure, but not so much the part about the actual nature of the carnival and where it's set up.]

We came by from another world. You're not actually on whatever planet you came from, right now - technically this would be a side dimension. Our tours take us all around the multiverse, if you're familiar with the concept.