Thor will grab your Bellybutton!!!
In Japan, when there is a thunderstorm, adults will tell children "Hide your bellybutton, or the Thunder God will steal your bellybutton." So, why so? Or rather, where did this originate? This usually happen during summer, when it is hot and humid. When there is a thunderstorm, temperature will drop tremendously. Adults would then find ways to tell children to wear their clothes properly, not to expose their belly, so not to catch a cold.