As revealed in "Spiral", the ring virus originally had an escape clause which allowed it to propagate itself, but Tomoko and her friends, not believing any of it, mischievously overwrote the part where the tape gave the solution as a prank. As a result, the virus had no means to inform its viewers on how to multiply itself, so it mutated when the next viewer of the tape, Kazuyuki, watched it and copied it for Ryuji Takayama. Two strains then emerged: a ring-shaped one, which would invariably kill its viewers within a week, and a spermatozoon-shaped one, which would lay dormant within the viewers unless they were ovulating women, whose ovum would be infected by the virus and transformed into a Sadako clone. This was because Sadako wanted to be reborn, something she could not biologically do because she was intersex. Finally, though the original tape and its copies had been disposed of by the events of "Spiral", the virus found its way into a new media: Kazuyuki's journal, which his brother published after his death in a car accident. Kazuyuki's survival was actually not because he copied the tape for Ryuji, but rather because he unwittingly helped the virus propagate. This was why Kazuyuki survived where his wife and daughter, who also copied the tape per his instruction, did not.