[Icemaster]

A joke is lowering someones chair or filling their lap drawer with shipping peanuts. Since it was done on a company owned asset, you've got obligations to address it. HR would want you to counsel, document, and drop it in his file (mine would anyway...).

Reality, call him to your office, ask him what manner of apology he's going to offer the other employee, his SO and kids (if applicable). Ask him how pissed he'd be if the tables were turned. Screws up again, then it's formal.

Human Resources should be honest about themselves and be renamed Risk Mitigation. There's no "human" in Human Resources.