Guess this sound! Bad clutch?

Picked up this ‘68 Barracuda a few days ago that hasn’t been run in several years. I freshened the fluids, etc, and it started right up. I noticed a strange sound coming from the hump near the firewall that goes away when I depress the clutch pedal.

Hopefully you can hear it in the video, you might have to turn up the volume. What’s this sound?