1. Scootaloo is chicken
Origin::
At S1E17 (Stare Master) CMC is helping Fluttershy rescue her chickens back. When on way. appel, apple Bloom teases Scootaloo as "Chicken". This thing annoys Scootaloo very much. This thing start spreading many sites such Memebase, Know Your Meme and more. Many fans are creating silly afbeeldingen e.g.: Food which chicken flavoured, areleady photoshopped door switching the chicken with Scootaloo.

meer info in: link

2. Rarity is marshmallow
Origin:
Due her jas color, she known to be heemst, marshmallow door fans. fans makes many fanart like a heemst, marshmallow with Rarity's mane.

meer info in:link

3. Fluttershy is a tree
Origin:
On S1E21, Mane 6 is on way to Appleloosa door train. Ponies are chatting in train and Fluttershy is appeared and say: "I'd like to be a tree...". This thing are keep spreading anywhere.

meer info in: link

4. Colgate/Romana/Minuette's hair is Toothpaste
Origin:
One of background pony is known as Colgate/Romana/Minuette is zei as toothpaste. Because one of her name is same as one of the toothpaste brand: Colgate. Also her mane and tail is designed as toothpaste.

meer info in: link

5. Pinkie Pie can break the 4th wall
Origin:
Pinkie Pie who known of her silliness are zei can break the fourth uithangbord like what she do in S1E9 and S1E21. Many fans made fanart like she can pass the screen and other.

meer info in: link

6.Blob Ponies/ Chubby Ponies
Origin:
On Deviantart. A user called Setacy is make a fanart of chubby ponies with simple face features.
This quite populair on Tumblr and there are a ask blog about it.

meer info in: link

Links:
1. link