Her cutie mark is two droplets of pee, and her special talent is being able to hold ridiculous amounts of urine in her bladder
She was challenged to a pee holding contest as a filly, and she won by holding it for 6 hours. She won the contest and received her cutie mark that day
She’s quite proud of her talent as well. When other ponies brag that they can write their name in the snow with their pee, she’s quick to one up them by spelling pneumonoultramicroscopicsilicovolcanoconiosis and still having enough left over to also write her name
One time she held it for like a month and everyone thought she was pregnant bc her bladder bulge was getting too big.
She just forgot to go and ended up pissing with the force of a pressure washer
She turned a small outhouse hole in the ground into a decent sized saltwater pond, so local engineers rigged up a drain field for her
She’s a very multipurpose pony with a lot of pent up piss