What you are seeing here is a "SOLID OBJECT" It's not compression artifacts, pixels or dust.
|SOHO - EIT Consortium, ESA, NASA|
"The compression artifacts are particularly obvious when a particle (cosmic ray or solar energetic, charged particle) hits the CCD detector on the spacecraft. The compression scheme has a hard time mathematically representing sharp, single or few-pixel features, and you get a characteristic pattern of a bright dot in the middle of a compression block (a subsection of the image) surrounded by a pattern of dark dots." -- (Dr.) Joseph B. Gurman, STEREO Project Scientist
It's interesting to note, The Russians claim their telescope TESIS stopped working on the 18th of January due to a faulty battery, just as NASA claimed SOHO malfunctioned on the same day, Both one day after these spheres showed up! [source]
Cassini Captures UFO
Manmade Object Approaches Earth - AL30