About
Inside the Cake is an exploitable image series spawned from the 2015 MLP movie Equestria Girls: Friendship Games. It typically consists of images with three panels; characters Pinkie Pie and Fluttershy are shown in the first two panels displaying the inside of a cake, while the third panel shows the reactions of Celestia, Luna, and Cadence.
Origin
The frames used in the meme are taken from the 2015 My Little Pony: Friendship is Magic spin-off movie, Equestria Girls: Friendship Games.[1] During the judging of a cake-baking contest, Pinkie Pie is shown cutting her cake in two and sliding one half away to reveal a reproduction of The Mona Lisa[2] by Leonardo da Vinci (shown below).

The scene begins at around 37:20 in the following video:
Spread
The first use of the scene as an exploitable image set was most likely a thread on 4chan’s /mlp/ board.[3] It began with the OP posting three sequential frames from the original movie; later in the thread, another user suggested that the middle frame would work as a template for an exploitable meme (shown below).

Crossovers with other memes and injokes within the MLP fandom are common. Examples include “That Was a Terrible Surprise” (below, left), “Pinkie’s Refrigerator” (below, center), and the Lyravator GIF (below, right).



Various Examples






Search Interest
Currently unavailable.
External References
[1]MLP Wiki – My Little Pony Equestria Girls: Friendship Games
[3]4chan Archive – Original Thread