Know what sets us apart from the animals? It's the fact that we know our bottoms are attached to us, and therefore part of our own bodies - rather than, say, a strange alien creature trying to creep up on us.
Dogs, however, seem to be regularly freaked out by the lurking presence of their own tails - as demonstrated by this daft pooch, who must have been feeling pretty dizzy by the time filming had finished.
Chill out, mate! It's your own tail! It's not going to attack you!
(A polite hat-tip to YouTube Petsami for highlighting this video.)
Mind you, dogs are quite often confused, aren't they? Take a look at this little lot...