Place the baked cake into a medium bowl and use hands to crumble the cake into very small pieces. Add in the frosting and vanilla and stir or use hands to fully incorporate the icing into the cake.
Separate the cake dough mixture into 3 bowls, equally. (If dying 3 colors, if not, separate into however many colors you plan to dye.) Add about 25 drops of food coloring into each bowl: (for green: 25 drops green, for orange: 13 drops yellow, 12 drops red and for purple: 13 drops red and 12 drops blue). Stir the dye into the mixtures well and add more color until you get the color you like. Freeze for at least 10-15 minutes.
Roll the cake pop dough into 1 ½ inch tight balls. Place on parchment and set in the freezer. Melt ⅓ cup of the white chocolate in 15-20 second increments in the microwave. Stir well between each time you heat. Pull several cake balls at a time and dip a cake pop stick tip into the melted chocolate and then press the stick into the cake pop half way (see image above). Complete with the rest of the pops and freeze another 15-20 minutes, and up to several hours.
When ready to coat the cake pops, heat the rest of the melting chocolate in the microwave again in 15 - 20 second increments , stirring well each time, making sure not to over cook.
Dunk each cake pop, straight down into the bowl of melted chocolate and slowly lift up, allowing excess to fall off. After about 10-15 seconds, place in an upright position to dry--in a box, styrofoam, or cup. Sprinkle with sprinkles, crushed Oreos, add eyes and more.
Store these cake pops covered in the refrigerator for up to one week.