Flickering Lights

Finding electrical issues can be difficult. In this scenario we had flickering lights in random rooms at different times within a structure. It didn't seem to be any particular area in the house and the issue was occurring at random times. A multimeter was placed on the incoming wiring in the sub-panel and a Go pro sat recording the meter all day. We were able to playback the footage and see that major voltage changes were occurring. If the issue happened and nothing was picked up on playback then the issue would lie somewhere in the panel in itself (downstream away from test meter reading). Since we were able to capture the issue (When lights flickered 240v would change to 120v to the whole panel) we know the issue is coming from the main panel (upstream) next to the power company meter. Once the main panel was opened the breaker to the sub-panel was located, turned off and removed. Turns out there was a dead frog and lizard on the contacts. The contacts were cleaned with blasts of air and the dead creatures removed (Without touching ANYTHING METAL!). A new breaker was installed matching the model of the old. Problem found and corrected!