How did our beloved Thelma earn her rather...unique cutie mark? I mean, we've seen nothing else like it in the show (in that it depicts her head).

4709214

She... um... she's a fakie?

My fakie pony theory states that fakies are a species of pony born with cutie marks, which is why they don't make sense.

Also, she's a Princess! Her mother is Princess Rinse and Spit of the Fakie Empire.

4709219 Hmm...I'll have to look deeper into this matter...