Foureye butterflyfish

Their name explains how this butterflyfish fools predators.  Although foureye butterflyfish really have only two eyes, they have 2 large eye spots (false eye markings) that confuse predators.  Their true eyes are hidden to some extent, by the black band that runs through the eye.  A predator taking a quick glance will see the large eye spots, and might think the fish is much larger, and also think that the head of the butterflyfish is at the tail end.

False eye spots are not uncommon on reef fishes.  This fish was about 4 inches long, and the photo was taken about 20 feet deep.