Smarty Pants used to be just a normal plush toy owned by Twilight Sparkle, until one day the unicorn had a mental breakdown and tried to use her to create a "friendship problem" by casting the Want-It-Need-It spell on her to make a group of fillies fight over her. Unfortunately, the spell worked too well, and soon everypony in Ponyville was thrashing each other to get their hooves on her! Eventually, Princess Celestia had to intervene and set everything right, using her alicorn magic to dispell the Want-It-Need-It spell and release Ponyville from its hold.
However, such uncontrolled release of magic like the one performed on Smarty Pants does have its side-effects... While in the care of Big Macintosh, who had taken her back home with him after the incident, Smarty Pants woke up one day to find that something strange had happened to her--she had woken up! She was alive!
The excess magic that had been poured into her from the Want-It-Need-It spell had stayed inside her after the spell had been cured, granting her sentience! She could remember everything from when she was first stitched together to when she was given to Twilight, all the way to this present moment! After testing out her new legs and getting used to walking around, Smarty Pants left Sweet Apple Acres to explore this new world that was open to her...
Smarty Pants can only be seen in her living form by one adult at a time, and only if she wants them to see her. If any adult is looking at her that isn't the one she wants to see her, she must freeze completely still, even if she is interacting with the adult she wants to be seen by. The only exceptions to these quirks are Twilight Sparkle, who has a more personal attachment to her than any other pony, and Pinkie Pie, who is crazy enough to perceive her. Children can perceive some things differently than adults, so they can see and interact with Smarty Pants whenever they want. Smarty Pants loves children and will play with them when given the chance, but the one pony she loves more than anypony is her mommy, Twilight Sparkle...
Smarty Pants has no vital organs, with her insides being made completely out of fabric and fluff. However, her newfound sentience has gifted her with a set of working digestive and reproductive organs, all made out of soft yet durable fabrics. Anything she eats will be broken down in her stomach, and any unused portions of her meal will be turned into mounds of cotton in her intestines to be pushed out of her rear. This is also true for any living meals she ingests, though she hasn't discovered the concept of vore yet... Yet... She is, after all, very naive, and could easily be shown just how fun both soft and hard vore could be...
--Smarty Pants met a cute tiny fleaboy named
Drizzit and found him to be very funny and sweet. He also found her to be very soft and warm as well as friendly and cute, and after the two of them got to know each other,
Drizzit agreed to not only live inside Smarty's body, but also let her be his giant plush pony girlfriend!
