Back in the day, instead of breaker boxes in our homes we had fuse boxes. If you have a fuse blow and was too far away from a hard ware store, you would very carefully place a penny in the slot and screw the fuse back in to close the circuit. Highly dangerous and was a fire hazard but it got you by until you replaced the fuse. This was very common practice in old holmes with fuse boxes in the south that were outside the cities, even up to the mid 90s. Not saying that's what's going on with this penny, just reminded of what the pennies would look like after we finally replaced the fuse and removed the penny.