In advance: Prepare base board and fondant trims. Tint fondant: 40 oz. each blue, green; 6 oz. violet; 4 oz. each black, brown; 2 oz. light burgundy; reserve 2 oz. white. Roll out 1/8 in. thick unless otherwise specified. Paint color details with Pearl Dust or Color Dust. Attach fondant pieces using damp brush.
Base board: Roll out blue and green fondant. Cover top 9 1/2 in. with blue, bottom 11 1/2 in. with green. Reserve remaining blue fondant. Use veining tool from set to mark hills. Paint hills with Goldenrod, Spruce Green and Lime Green Color Dust. Paint water with Sapphire Blue Pearl Dust and Periwinkle and White Color Dust to gradually lighten color toward the top. Use patterns and Deep Pink, White and Periwinkle Blue Color Dust to paint extra large, large, medium & small petal outlines in the water.
Banner: Roll out white fondant. Use pattern to cut out banner (flip pattern for second half).
Jellyfish: Roll out burgundy fondant. Use patterns to cut two large, one medium, one small. Attach. Cut six 1/8 x 2 in. strips for each jellyfish; attach for tentacles. Paint spots using Deep Pink Color Dust.
Plants: Roll out white and violet fondant. Use patterns to cut out large, medium & small plants with white top, violet base. Paint outline with Purple Color Dust. Paint bases with Purple, White and Deep Pink Color Dust and Sapphire Blue Pearl Dust. Paint spots with Deep Pink Color Dust.
Coral: Roll out violet fondant. Use patterns to cut out one extra large, two large (flip pattern for 2nd), one medium and two small. Paint outline with Purple Color Dust. Paint details with Purple, White, Deep Pink Color Dust and Sapphire Blue Pearl Dust.
Net: Add 1 teaspoon Gum-Tex to 6 oz. reserved blue fondant. Roll out. Cut using pattern. Set on waxed paper-covered board. Roll out brown. Use pattern to cut net rim; attach over net. Cut dowel rod to 7 1/2 in. long; cover with brown fondant. Use veining tool to mark woodgrain lines. Let dry 2 days.
Bake and cool cake and two cupcakes. Ice cake sides and background areas smooth; ice cupcakes smooth. Use tip 3 to outline and fill in sponge holes, teeth, mouth and tongue; pat smooth with finger. Use pattern, to mark glasses. Ice lens areas smooth. Use tip 3 to pipe and fill in irises and pupils; pat smooth with finger dipped in cornstarch. Use tip 3 to outline all details except hand holding net.
Cover SpongeBob with tip 16 stars. Pipe tip 3 dot freckles, stripes on socks, shoelaces.
Roll out black fondant 1/8 in. thick. Use pattern to cut out glasses. Position on cake. Pipe tip 3 corner highlights. Position net handle. Use tip 3 to outline hand and fingers over handle; cover with tip 16 stars. Position cake on prepared board. Outline banner and pipe message with tip 3; attach with icing. Pipe tip 3 net lines. Position net using cupcakes for support, attaching with icing.
* Combine Leaf Green with Lemon Yellow for green shown.
* Combine Violet with Rose for violet shown.
* Combine SpongeBob SquarePants Brown with SpongeBob SquarePants Red for brown shown.