During an investigation at the New York City Public Library, Egon was using a Stethoscope to listen for the alleged Library ghost. Egon sat next to a table in the Main Reading Room listening with his stethoscope. He held the end against the underside of the table. Peter Venkman noticed Egon and sneaked over then, in a faux zombie voice, uttered, "Egon..." Egon perked up. Peter rapped the table with his knuckles then slammed a hardcover book down. Egon was startled and jumped. He finally noticed Peter and Ray Stantz. Egon wore the Stethoscope in the first Ghostbusters commercial.
- IDW Comics