Pumpkin Cake and Pound Cake

Depiction in the series
The two foals are first introduced in the episode Baby Cakes as newborn foals. Where they are visited by Twilight Sparkle and her friends in the hospital. However, they are much surprised to find out that Pound Cake is a male Pegasus and that Pumpkin Cake is female Unicorn, but despite the fact that both their parents are Earth ponies. Though, Mr Cake explains by referring to distantly related Unicorns and Pegasi in both his and and Mrs Cake's family trees. Rarity,Rainbow Dash, Twilight Sparkle, all warn and caution the Cakes by that young Unicorns can exhibit bursts magical power, and young Pegasi can be quite a hooful once they learn how to use their wings.

The next scene shows them playing with Pinkie Pie on what she called it their "Monthiversary", despite them being only one month old. Pound Cake and Pumpkin Cake, are already able to run around the house. This is actually true with real life young ponies, who can walk mere hours after being born. That same day the Cakes are in much need of a babysitter, and after, Rarity, Rainbow Dash, Applejack,Fluttershy,and Twilight Sparkle all decline the offer, they then ask Pinkie Pie reluctantly to take care of Pound and Pumpkin Cake, while Mr and Mrs Cake are off delivering a catering order.

For Pinkie, this proves her much more work and less fun than she had expected. When Mr and Mrs Cake leave, Pinkie's attempts to calm the foals down, including trying to feed them or even bathe them, but it all ends up with them crying. Each time, the way Pinkie can calm them down is by pouring a bag of flour over herself, which amuses the foals.

Later in the episode, they also prove that the warnings that Twilight and her friends gave, were true. Pound Cake, however, he makes it very difficult for Pinkie to chase him after he starts flying as well as walking on the ceiling with much help from his wings; Pumpkin Cake, she uses her unicorn magic to levitate herself, phase herself through a laundry basket that Pinkie had trapped them under, and she break chains the toy chest.

After eventually it's Pinkie's turn to break into tears, when she had realized that she couldn't keep the two foals under control. That's when the two stop playing around; and attempt to cheer up Pinkie by imitating what she did for them- emptying a bag of flour over their heads. Next scene, it shows the foals peacefully sleeping in their crib,which gives Pinkie the chance to clean up Sugarcube Corner, before Mr and Mrs Cake arrived home.

Pound Cake, he displays a habit of pounding on items and Pumpkin Cake shows she has a habit of chewing on items that aren't food, Which includes, a bath towel,several toys, and a table cloth. She also tries to chew on the stick of a broom, Pinkie uses.

Appearances
Baby Cakes

A Friend in Deed

Ponyville Confidential