If you see my watermark on a drawing or painting that I made but isn't shared by me or is under a different account, then the person likely stole it. If someone decided to remix a drawing I made and give PROPER crediting, then I would be okay with it. I will be hiding my watermark in the drawings I share :D.
Hopefully, someone else doesn't have a similar watermark to mine, I made mine up by taking the first 2 letters of Dragon and Axolotl and got Drax! I wrote it a few times with a pencil and drew it on scratch with my finger, and I decided that this one you're seeing will be my official watermark! (It was also the best one I got). I know it's unlikely someone is gonna take my art, but whatever.