Heater cord failure.

Far from cool.
One of our 1500 watt oil filled heaters had an impressive electrical spark/flame in the line cord. It was not a short, but a high resistance breach. If there was anything around that could burn near breach it would have easily started a blaze. Fortunately we were right there.
When leaving heaters on when we are not there, I always try to remember to check wires being far enough away from something that could burn, it would have saved the day in this case.
Y9-07-16