User blog comment:P進大好きbot/Ill-definedness of BIG FOOT, Little Bigeddon, and Sasquatch/@comment-34422464-20181207214757/@comment-35470197-20190101224508

As I wrote above, the definition of BIG FOOT contradicts the usual first order set theory. See the comment here. Therefore we need unusual set theory there, which is unspecified in the defintion. That is why I said that it is ill-defined.