Carve a Minion shaped oval out of the cake.

Reserve all the cake scraps for later.

Spoon all the frosting colors into individual pastry bags, each fitted with a star tip, reserving about ½ cup of the black.

Place the reserved black frosting into a pastry bag fitted with a #4 round tip.

Decorate the cake by piping stars all over the surface and sides.

Start by making two silver gray circles for the Minion's goggles.

Pipe a small black circle in the middle of those circles then fill in around the black circle using white frosting.

Pipe a black band on either side of the goggles.

Pipe yellow above and just below the goggles.

Pipe on the black and white striped prisoner uniform.

Pipe a line around the straps to the uniform and pipe on the outline of a pocket in the middle of the uniform.

Pipe white stars inside the pocket border then pipe on a prisoner number over the white stars using black frosting.

Pipe on a black smile.

Glue together the cake scraps using frosting and cut a rectangle prisoner hat out of the scraps.

Attach the hat to the top of the Minion and pipe on black and white stripes.

Crumble all the remaining cake scraps and blend together with a tablespoon or two of frosting.

Use this cake ball mixture to shape two arms, two legs, and two shoes for the Minion.

Pipe yellow frosting over the arm then pipe on black gloves.

Pipe white frosting over the legs then black over the shoes.