Totally.
I used to come up with story ideas by the day, and I would quickly start working on characters that didn't have much depth or personality. One of these was Psari (pronounced sari, Greek for fish). In the story, the main character comes upon a civilization of water people (people literally made of water) and they share their wisdom. Psari was the stable girl who took care of the seahorses. Clever, I know.
Psari was mentioned once in the original draft of the story. Here's the line: "When I was helping a river girl named Psari(yes, Psari, it’s Greek for fish) at the stables, I bonded with those huge sea horses."
I wrote this when I was eleven.
I wanted to give Psari more time, and I thought she could be a new love interest or someone who helped the MC on their journey. I asked my friend for help on this, and she said that Psari and the water people as a whole could have a power that allowed them to shapeshift.
I had been pretty set on having Psari take on a new name, Circe, and be one of the side characters' love interests. It was a whole thing, and he was eventually going to choose her over the other corner of the triangle.
Then the brainstorming came.
Long story short, Psari ended up threatening the side character if he didn't choose her over the other corner of the triangle (named Clarrie [yes, weird name.]).
So Psari went from a lowly stable girl to a love interest to a very violent love interest, and I haven't thought about her since I wrote this post.
Thanks for listening to my TedTalk.