For about two hours, the virtual landscape of Second Life filled with golden rings and the distinctive two-tone ding of Sega's popular Sonic the Hedgehog games. The rings' listed creator was the fictional "Dr. Robotnik," a character from the Sonic games. However, the deluge of rings was not some form of cross promotion, but a viral attack of self-replicating objects, known less than affectionately as "grey goo."
Read the complete story here. (Security Focus)