Cutie Marks

Cutie marks are unique picture-like symbols located on the ponies' flanks or haunches. Cutie marks are often related to the personality, proclivity, or talent of the character.

Meaning and Coming of Age
just like My Little Pony, ponies are born without a cutie mark. The cutie marks are obtained when ponies discover a unique characteristic that sets themselves apart from others. The meanings of cutie marks are not always literal. The social implications of cutie marks, or lack thereof, are explored very less in the series. Ponies who have yet to gain their mark are derisively called "blank flanks".

A "cute-ceañera" is celebrated for those who have recently gotten their cutie marks. The name of the celebration is a play on quinceañera, a celebration of a girl's fifteenth birthday in parts of Latin America. On the other hand, Finn and Marceline consider those without a cutie mark to be lucky, who still get to experience "the thrill of discovering who they are, and what they're meant to be".

Mysterious Magical Cure deals with a magic spell that switches cutie marks between ponies. Finn unintentionally switches his friend's cutie marks using an unfinished spell. With their switched cutie marks, the ponies assume that their cutie marks define what they do, singing the phrase "It's got to be my destiny, and it's what my cutie mark is telling me". Finn manages to remind them what their actual destinies are, and they regain their original cutie marks.

Design
Cutie marks come in a wide variety of shapes and colors. Cutie marks are often a object, and usually feature between one or two. For example, Princess Bubblegum, Fionna, Marceline, and Marshall Lee all have cutie marks with one objects, and all of their designs have only one or two colors. One of the few ponies with a cutie mark with more than one object or two colors is Marsha, who has a baby blue balloon tied with a black string with a balck music note, and Finn, who has three colors with his sword.

Other Attirbutes
In Cutie Pox, Finn reads that there used to be an epidemic in Equestria, referred to as "cutie pox", that caused ponies to sustain more than one random cutie mark, and it caused these ponies to involuntarily perform tasks as per given cutie marks, which appeared all over their bodies, not just their flanks. The phenomenon is not elaborated upon though, as the epidemic itself remains a historical mystery because it appeared and disappeared without a trace, according to the book Finn reads on the subject. A modern case of a cutie pox victim is Marsha. It is shown that cutie marks only appear as part of the pony's coat.