An eyeworm (from the German Augewurm) is a term I just made up for seeing a shape in things that you cannot unsee. A virus stemming from the pareidolia family of psychological paraphernalia, examples include that smiley face in the water stain of the ceiling above your bed that you wake up to every morning that seems to be scorning you as you try to gather the strength to face the day ahead, and dog masks on ducks.
Like earworms, the shapes that you cannot unsee are often prompted by something catching: a traumatic event or a former lover's face, so that you are revisiting those memories time and time again. When your mother tells you that your father ran away to be an astronaut and that's his face in the Moon, this is something you can't unsee, unlike clouds, which morph into something terrifying, and then a hopping bunny. Londoners who have had the misfortune to have experienced the goatse image almost had to endure a few years of wanting to gouge their eyes out when a version of the Olympic Logo was unveiled* with remarkable graphical similarites to that which must not be seen again. Fortunately, it didn't make the grade. Unfortunately, what is the logo is something that for someone who read copies of Heavy Metal at a formative age looks like Lisa Simpson giving Vaugh Bode's Cheech the Wizard a blowjob. Ok, it doesn't really look like that, but once I saw it...
The only way to unsee eyeworms is to deface the object, replace that seen with something more palatable, or--like earworms-- wash your eyes out by looking at cute kittens climbing into boxes on internet videos.
*link safe for those who have not seen that which should not have been seen in the first place.