Best response ever
As a girl, I don't really get teased a lot for ponies, not at all really. But one thing I've learned about being "weird" is that the more you own it, the less people give a crap. The more power they think that they have over you, the more they will try to control you. If they think that you are strong, they will leave you alone. You do not need to be strong, you just need to make them believe it. Be assertive, not aggressive. It's basic nature. Just watch animals in the wild sizing each other up.
I'm all for ignoring but sometimes that doesn't work. What helped me in the past is pretending to agree with they bully, or laughing along with them. I'd only retort if someone is being very mean.
"Isn't that a girl show?" - "Is it?! Oh my goodness really?! I had no freaking idea!!! Thank godness I had someone so perceptive and smart to inform me of that!!! Oh my goodness thank you for pointing that out!!! You are such a freaking genius!!!" - "No way, I thought a show about colorful talking singing pretty ponies was aimed at adult men 40 and up" - "Please don't tell me you just figured that out" - "Do you really need to ask that?"- "Genius alert!! My Little Pony is a show for little girls!!!"
"Isn't that girly?" - "Yes." "Noooo, really?"
"Are you gay?" - "Why do you care?" - "Are you a homophobe?" - "No, why do you ask?" - "You seem like a very nice boy, but sorry, I'm not gay." - "No, I do not want to go out with you." - "Don't you have anything better to do?"
Any other questions "is your life really so boring that you have to harass other people to make it interesting?" - "Why are you so interested in me?" - "Why do you care?"
Or just go off doing something that you're interested in, like reading, drawing, or just pretend to be doing something more interesting than listening to them. Don't let them get to you