Go to a
mirror, and stand very
close to it with your
head up straight. Look
carefully at your
eyeballs, then
slowly tip your
head to one side. Your
eyeballs rotate the
opposite way to
your head so they remain on the
horizontal plane!
Not
side-to-side, or
up-and-down, but
spin around the
axis that goes through the
pupils.
I never knew eyes could do this!
Someone! Tell me what this
phenomenon is called!
An addendum to this, months later... If you do this too much, your eyes may break free and begin spinning freely. Very freaky.
Just kidding.