Well, it's probably just a very large mutant Bidoof, so the question most likely won't be necessary. But on the super ultra slim hypothetical chance that it's something else (and even if it isn't), the group is perfectly welcome to believe that whatever shows up is a god. Whether or not it really is a god is another question altogether.

It will certainly seem like a strong possibility even to those with no particular affinities towards researching this kind of thing, though.