Melt Candy Melts following package instructions.
Marbleize white and cocoa Candy Melts by adding a small amount of melted candy in another color or variety; mix slightly (Do not overmix; you want to see streaks of color.) Fill seashells mold with melted candy. Gently tap mold on counter. Refrigerate until firm. Unmold. Dust with Pearl Dust.
Pipe color details in molds using melted candy in parchment bag or disposable decorating bag with a small hole cut in tip, or paint melted candy into areas. Refrigerate until firm. Fill remainder of mold with melted candy. Refrigerate until firm; unmold.
Fill Candy Bar Mold with melted dark cocoa Candy Melts. Refrigerate until firm. Fill cordial cup mold with melted peanut butter Candy Melts. Refrigerate until firm. Unmold candy.
Pour a layer of nonpareils in pie pan. Melt white candy in parchment bag; cut bag and pipe outlines in coral shapes on top of nonpareils. Immediately pour additional nonpareils over coral, covering completely. Refrigerate until firm.
Bake your favorite 2-layer 10 in. round, 3-layer 6 in. square and mini wonder mold cakes; cool completely. Place round cake on cake drum; spatula ice with blue buttercream icing. To support square cake, insert dowel rods towards back of round cake. Place square and mini wonder mold cakes on cake circle cut to size. Spatula ice square cake with tan icing; immediately press granulated brown sugar onto iced cake. Stack on round cake. Spatula ice wonder mold cake with tan icing; press brown sugar onto iced cake. Stack on square cake; if desired, insert wooden skewer to secure.
Tint piping gel blue; spatula ice top of round cake at edges. Sprinkle granulated brown sugar in area around square cake. Attach candy bar door, seashell candy windows and house corners; cordial cup and seashell candy turrets. Attach coral candy on round layer sides; add tip 352 green buttercream sea plants. Arrange seashell candy around bottom of round layer; sprinkle drum with granulated brown sugar. Attach sea creatures and other candies on cake sides.