Make cookies. Prepare and roll out cookie dough following recipe directions. Cut cookies using SpongeBob cutter from set. Bake and cool cookies.
Outline and fill in cookies. Prepare Color Flow Icing following recipe directions. Tint portions light yellow, dark yellow, red, blue and black. Reserve some white.
Use tip 2 and full-strength light yellow icing to outline cookie. Use thinned light yellow icing in a cut parchment bag to fill in. Immediately use tip 3 and thinned dark yellow icing to pipe dots. Let set 24 hours.
Decorate cookies. For eyes, use tip 3 and full-strength white icing to pipe eyeballs. Pat smooth with finger dipped in cornstarch. Use tip 1 and full-strength black icing to outline eyes. Use tip 2 and full-strength blue icing to pipe iris. Pat smooth with finger dipped in cornstarch. Use tip 2 and full-strength black icing to pipe pupil. Pat smooth with finger dipped in cornstarch.
For teeth and eyelashes, use tip 1 and full-strength black icing to outline teeth and to pipe eyelashes.
For mouth, use tip 1 to and full-strength red icing to pipe mouth, smile creases and mark beneath teeth. Let set 1 to 2 hours.