An EAS tag includes a cap with a tack shaft and a body with a clutch for receiving and retaining the tack shaft. An aperture in the body gives access to the clutch. The cap is concave and shaped to fit over the body, and the tack shaft extends into the concavity of the cap. The shape of the body and cap and the position of the tack shaft provide an initial resistance to twisting the cap with respect to the body. Both the cap and body may have additional features with interact or interlock to prevent the cap from being twisted. Additional, the cap may have areas of reduced thickness to induce breaking away of parts of the cap when excessive stress is induced in the cap.