Desert Prospecting
Find Voodoo Dolls in the ground in the desert, near the cemetery in the upper right corner of the desert area. Locate the gigantic fossil by the cemetery and dig in the surrounding area. If you do not find any Voodoo Dolls, leave the area, return and try again. Eventually you will unearth Voodoo Dolls.
Madame Zoe
Once you complete Madame Zoe's four tasks, she will offer to move into the town. Accept her moving into town and help her build her new home. Once she becomes a town resident, she will let you use her Fortunite Crystal ball. The Fortunite Crystal gives you Spooky Essences. You have a random chance of getting Voodoo Dolls.
Home Fortunite Crystal
If you do not want to let Madame Zoe move into town, you can build your own Fortunite Crystal ball in your home. Be aware that the ball is large and takes up 53 blocks of space, so you will need a large empty space within your home. Use the Fortunite Crystal ball and get a Spooky Essence. You have a chance of getting Voodoo Dolls each time you use the crystal.
Star Level
You cannot find Voodoo Dolls in "MySims" until you reach a Star Level of three or higher. If you are experiencing difficulty finding Voodoo Dolls, you may have missed this step. This also means that you cannot complete Madame Zoe's first task until you reach at least the third Star Level because you will need Voodoo Dolls. You thus cannot when rely on getting your first Voodoo Dolls from her Fortunite Crystal.