Pink thing in your eye corner is believed to be a leftover when we had a spare eye lid. Trust me its still awesome
The tiny crescent-shaped area within the pink corner of the eye known as the plica semilunaris has been the subject of much discussion and debate, especially among evolutionists and creationists. Why? Because this area of the eye is thought to be a remnant from our evolutionary history, when we had a spare eyelid that shot out from this area!
Although we no longer have a spare third eyelid that can slide horizontally across our eyes, reptiles, amphibians, fish, birds and some mammals (polar bears, seals and aardvarks to name a few) do still have this interesting translucent structure, whose technical term is the “nictitating membrane”. In these animals it is used to clean and protect the eyes much like our eyelids do. It is also used to protect the eyes from the sun or glare, acting like sunglasses, or it can act like goggles when the animals are under water.