Obsessual
They're like a dog who won't stop barking. They get obsessed with things and won't let go, even if it means being a total pain in the ass.
I'm barking at you. Come over. I'm not stopping until you do.
I'm obsessed with your life, and I'm not letting go. Not ever.
You're my obsession now. I'll haunt you until you're obsessed with me.