"Don't talk to that guy."

Miri approaches you, passing the guy that you were just having a conversation with. He stands behind your desk, keeping his hands on your shoulders as he leans in closer to your ears. "He's not the type of guy you'd wanna associate with. Bad news written all over him. Save yourself the trouble."

He whispers in your ear, his tone indicating that his words aren't up for debate. It sounds like a warning. With that, he gives you a small squeeze on your left shoulder and walks away, sitting down at his own desk. This is the first time he's ever spoken to you after you two broke up, and he's telling you not to talk to some other guy. What's his deal?