Hysteresis and proteresis are two complementary phenomena used in integrated circuits. Hysteresis is a widely known and applied phenomenon, while proteresis is used less frequently. Hysteresis exhibits a delayed response, whereas proteresis demonstrates an advanced response. This paper presents the design of a single CMOS circuit that exhibits both hysteretic and proteretic properties and has been named as ProHys switch, thus leveraging the benefits of both phenomena. The circuit can switch between hysteretic and proteretic operations based on the control input signal. It maintains the noise immunity of 0.2V in each state. Proof of concept is established by post-layout simulation of the proposed circuit in TSMC 180nm CMOS technology and occupies an area of 41µmX48µm. It is demonstrated to work in the temperature range of -20°C to 100°C and up to a maximum frequency of 10MHz. This paper also explores the possibility of using the proposed ProHys Switch as a Physical Unclonable Function (PUF) for security applications.