Slice each loaf of banana bread in half, and round out the corners to create 4 oval-shaped cakes. Place each cake on a piece of parchment paper.

Mix the cinnamon into the vanilla buttercream, and spread a thin layer over all of the cakes. Place these in the fridge for the buttercream to stiffen, then apply a thicker layer over buttercream onto the cakes.

Using your desired colour of cotton candy, begin attaching long pieces of cotton candy to the cakes, making sure to lay the cotton candy so that it looks like long, smooth guinea pig fur. For extra definition around the face, nose and neck, gently press down with your fingers to shape the cotton candy.

Spoon some melted yellow-coloured chocolate onto a square of parchment paper and make 8 circles for the ears. Then spoon some melted pink-coloured chocolate onto the parchment paper to make 4 little noses. Transfer these to the freezer until they are fully set.

Stick two dark chocolate chips onto each guinea pig for their eyes, and add the ears and pink noses.