Make cake. Prepare batter following recipe directions. Bake and cool cake. Place cake on foil-wrapped cake board, cut to fit.
Ice cake. Prepare chocolate buttercream icing following recipe directions. Tint black. Use spatula and black icing to ice cake sides and background areas smooth.
Decorate mask and hat. Prepare buttercream icing following recipe directions. Tint portions violet, rose, yellow and green. Use pattern and toothpick to mark mask on dinosaur head. Use toothpick to mark hat area on dinosaur tail, 3 1/4 in. wide at widest point.
Use tip 4 and yellow icing to outline mask with eye openings and to pipe an outline down center of hat. Use tip 4 and green icing to outline hat. Use tip 16 and yellow icing to fill in mask with stars. Use tip 16 and green icing to fill in hat with stars. Use tip 12 and yellow icing to pipe ball pompom. Pat smooth with finger dipped in cornstarch.
Decorate feathers and loops. Use tip 4 and rose icing to pipe a center line from top of mask to 1 in. from back of heel area, then curving toward feet. Use tip 4 and rose icing to pipe two curving branch lines, 2 in. and 4 in. from top of mask. Use tip 4 and rose icing to pipe random lines in various directions to create feather look.
Use tip 4 and rose icing to pipe three loose spiral accents on hat.
Decorate leaves. Use tip 366 and violet icing to pipe two rows of leaves on top edge of mask, staggering top leaves between bottom leaves.
Complete mask. Use tip 7 and green icing to pipe curved line above eyes. Use tip 7 and green icing to pipe dots at ends of curving line, above curving line and below eyes, 1/4 in. apart. Use tip 4 and violet icing to pipe dots around edge of mask, 1/2 in. apart.
Complete cake. Use tip 4 and black icing to pipe bead bottom border.
The star tip creates the most celebrated, easily accomplished decorations! The serrated edges of the star tip make ridges in the icing as you squeeze it out. Because fill in requires so much piping from the same bag, keep replenishing icing in bag.