Friday the 13th: The Series (1987)

S1E18 Brain Drain

A simple-minded man stumbles upon a cursed trefinator in a museum storage area—a device resembling a guillotine that moves spinal fluid between people. Unbeknownst to him, it also swaps intelligence. He decides to exploit this to boost his own smarts by targeting doctors at the museum. Jack and his friends get drawn into the chaos when Jack's former girlfriend and fiancée starts working there, making her the next intended victim of the trefinator.