Crumble the prepared cake into a large mixing bowl.
Remove the lid and foil from the cream cheese icing and microwave it for 30 seconds. Pour the warmed icing into the bowl with the crumbled cake.
Fold the cake mixture together until the icing is evenly distributed.
Scoop 1 tablespoon-sized balls onto a parchment or Silpat-lined baking sheet. Place the balls into the freezer to chill for 30 minutes (or up to overnight).
Melt the white chocolate bark according to the package directions.
Dip each truffle into the white chocolate and allow any excess to drip off before placing it back on the baking sheet.
Add the candy eyes to the truffle (make sure to add them before the chocolate sets).
Repeat with the remaining truffles.
Once all of the truffles have been dipped, pour the remaining chocolate bark into a plastic bag and cut a small end off the corner.
Drizzle the truffles with the white chocolate to create the mummy look.
Allow the chocolate to set completely and then store in an airtight container in the fridge for up to three days.