The Tails Doll Curse lists the various methods of summoning the Tails Doll.
Preforming The Curse
There are several different variations to performing the Tails Doll Curse. The following lists the most common methods, but is probably incomplete given the vastness of the Tails Doll mythos.
◾The Sonic R Curse - One simply completes Sonic R 100%, which will attract the Tails Doll to the person. This only works on the Sega Saturn and PC versions of the game.
◾The Tag Four Characters Curse - Interlinked to the Sonic R curse; a more direct way of summoning the Tails Doll. One selects Tag Four Characters mode after beating the game 100% and plays as Tails Doll on Resort Island. The practitioner goes to tag each of the characters, saving Super Sonic for last. This gives the Tails Doll enough power to break the Miyamoto Seal and enter into the real world.
◾The Bathroom Curse - One goes into a dark bathroom and shuts the door. Facing the mirror, they begin to sing Living in the City. Alternatively, one can instead sing Can You Feel the Sunshine or the ACID Remix, or use a recording. It is more effective if done backwards.
How the Curse Develops
For the latter two curses, the Tails Doll appears right away and offers the practitioner of the curse a deal: Become its servant or perish. Should you not accept the deal, the Tails Doll will attack the practitioner and likely devour their soul. In rare cases, the practitioner can outwit the Tails Doll or defeat it for a time. These victories never last; victory always comes at a price.
The Sonic R curse tends to develop different, and sometimes the Tails Doll doesn't appear right away for the other two curses. If this is the case, the curse starts to develop in a gradual way. It begins with a stroke of bad luck, starting with just minor inconveniences and then escalating to big things. Items start to go missing, and sticky notes with messages on them start to appear in their place. Eventually, the Tails Doll appears and, if it doesn't kill them outright, offers the practitioner the same deal as above.
Seven Pure Souls
While the Tails Doll typically ignores people who don't perform the curse, the Seven Pure Souls are a different story. They are watched by the Tails Doll intensely and may be attacked for no particular reason other than being the most desirable souls for the Tails Doll's tastebuds.