Next roll out the red fondant to 1/4-inch thickness. Using the bigger circle stencil, cut out the red circles with a sharp knife. Store any leftover fondant in a ziptop plastic bag so it won't dry out.
Roll out the white fondant and cut out the smaller circles. Store any leftover fontant in a ziptop bag.
Trace the lightning bolt shape onto the yellow sugar sheet with a black edible ink marker*. After tracing all of the lightning bolts, cut them out with sharp scissors and peel the plastic from the back.
Dampen the center of a red circle with water and place a white circle on top. Then, lightly coat the white circle with water and place a lightning bolt on top. Repeat with the rest of the shapes. Let the toppers dry completely before adding them to your frosted cupcakes.
*Edible ink markers can be found at most craft stores.