Why would an ex create an account to stalk me?

Anonymous
So I’m at least 99.8% sure my ex or her friend created a fake account and stalked me on. As soon as I noticed the account with 0 posts 0 followers and following 0 I knew it was a stalker and I messaged them, never heard back and now they don’t stalk me anymore or at least not to my knowledge. I know they stalked me cause I saw the account on multiple of my Instagram stories. And to make things better. My friend messaged her and she said something along the lines of “I saw you were connected to my ex (being me)” that confirmed it. So why would an ex (or her friend) create an account to stalk me
Why would an ex create an account to stalk me?
2 Opinion