for me if find it a poor OC when they start mixing different types of ponies just because it looks good, for example:
a pony with zebra stripes, bat pony ears, eyes, and fangs, changeling holes and dragon wings.
it just doesn't make any sense, how did this pony come to be.
On a side note, does my OC sound bad?
FEEL FREE to skip this part if you don't want to read a chunk about my OC, I tend to get carried away when I write/type
He is a unicorn called Snowflurry, he has a deep dark blue coat, a long wild mane that is royal blue that as it travels down changes to sky blue, icy blue, and finally white, same with his tail. light blue eyes and hooves (possibly white hooves, not quite sure).
He is an orphan who was raised by zebras, he originally was at an orphanage where he didn't fit in because he has trouble with talking to other ponies, he stutters, gets tongue tied and generally gets nervous.
He has a scar down his right side and a cracked horn, caused by being trapped in the orphanage when it caught fire. Because of this he generally hates heat and gets nervous around fire
Since his horn is cracked he has difficulty using magic in general, he can do simple magic like levitating ordinary objects as long as they aren't to heavy, but he excels at water and ice magic, as well as simple transformation spells (e.g. ice to glass), but if he tries other types of magic it causes migraines and if he pushes himself through other powerful magic spells it causes his horn to crack even more, damaging it more.
To compensate for his lack of magical abilities he delved into studying alchemy and potions and soon found a passion for the art, which his foster/adoptive parents helped hem develop and grow.
His cutie mark is a frozen/icy potion bottle
In his spare time he likes to make miniature ice sculptures, and the ones he really likes he turns into colored glass
By the time he grew up he became a competent aspiring potion maker and heard from his parents that a amazing potion maker lived it a town called ponyville and decided to head there to learn all he could from this potion master.
Since he has quite a difficult time communicating with other ponies, he often doesn't talk directly to others unless he is close to them, and even then not when in large crowds, instead he often leaves notes and gifts, including miniature glass statues
(I know the whole orphanage fire, scar and cracked horn aren't really quite in theme with the show, oh well. p.s. no one died in the fire (side note he got caught in there cause he thought his only friend was trapped in there for she was bedridden, but I digress))
Sorry for the longish description and thanks for reading, (trust me I could have gone way more in-depth XD) I think I have thinned it down to the most important parts that shape the main idea of my OC (but I have been known to write walls of text from here to kingdom come)
I will get round to writing the full thing in the OC section soon, I promise