Now this incredible illusion has an interesting history. Many years back, I chanced upon a still picture which looked like a ball of 'fluff' (click it on the right to see full size), where the outer ridges faded away to white. The idea was to stare at the centre, and it would gradually disappear. It was cool stuff at the time, and I made my own enhanced version much later with lots of little coloured blobs, and called it "Vanishing Fluff".
Years later, I found Michael's brilliant "Motion Induced Blindness" illusion. At the time I was shocked that anything so bright as those small dots could disappear.
All well and good, but how about if we combine the two effects into one illusion? Can we get away with making massively large objects disappear?! Yes, OH YES, indeed... have a look at this monster...
If you can't make it work, try sitting closer to the screen. If you still have trouble, then try this easier version