Some unique ideas for a baby shower cake include a cake made in the shape of a bouquet, with the flowers made of brightly dyed marshmallow halves, or a jungle themed cake made with green cupcakes and little animal figures. A Star Wars themed cake is also a unique choice.
Another unique cake idea is one in the shape of a onesie. If the gender of the baby is known, the cake can be decorated accordingly.
If the parents are affiliated with the Navy, or live a nautical lifestyle, a nautical themed cake is a unique choice. Using white and various hues of blue, including navy blue, as the base, the cake can be decorated with anchors and life preservers. If the dad-to-be is attending the shower, a unique cake for him would be a cake shaped like a cigar box, with Tootsie Roll cigars.
Diaper cakes, while inedible, are also very appropriate for a baby shower. A unique idea for a diaper cake is one in the form of a bassinet, with diapers forming the body of the structure and two rolled-up diapers forming the wheels. An unfolded diaper makes up the hood of the bassinet. The structure is held together with pretty ribbons, and a blanket lies on top.