Beat 2 cups softened unsalted butter on high speed until it's smooth and pale in colour.
Add 6-8 cups of powdered sugar, beating in one cup at a time until the mixture is smooth.
Add whole milk by the tablespoon until the frosting reaches spreading consistency (you'll probably need to add 3-4 tablespoons of milk).
Divide the frosting into 4 equal parts. Use food colouring to colour one batch of the frosting yellow, one batch of the frosting orange, and stir about 4 teaspoons of cocoa powder into the third batch to make the dark chocolate frosting.
Divide the fourth part of the frosting into two parts, leaving one part white and stirring 1 teaspoon of cocoa powder into the other part to create the light brown frosting.
You should end up with 5 bowls of frosting: yellow, orange, dark brown, light brown and white.
Lion Cupcakes:
Spread yellow frosting on top of each cupcake.
Roll the edges in red sprinkles and add two yellow candies for the ears.
Draw eyes, whiskers and nose on with a black gel frosting pen.
Tiger Cupcakes:
Spread orange frosting on top of each cupcake.
Draw on the stripes, eyes and nose with a black gel frosting pen.
Place on 2 orange candies for the ears.
Bear Cupcakes:
Spread dark chocolate frosting on each cupcake.
Spread a small amount of light brown frosting for the snout and place two brown candies for the ears.
Draw on the eyes and nose with a black gel frosting pen.
Monkey Cupcakes:
Spread the dark chocolate frosting over each cupcake.
Spread a small bit of light brown frosting for the snout and a little bit for the hair.
Pipe on a small amount of the white frosting for the eyes.
Add chocolate candies for the pupils and the ears.
Draw on the nose and a smile with a black gel frosting pen.
Owl Cupcakes:
Spread each cupcake with the dark chocolate frosting.
Pipe 2 small dollops of white frosting where the eyes should be and add two Oreo cookie halves on top.
Pipe two small dots of white frosting on top of the Oreo cookies and add two small chocolate candies for the pupils.
Add an orange candy for the nose.
Notes
You can use homemade cupcakes, cupcakes made from a boxed mix, or even pre-made cupcakes.