...that was on purpose: I came to the conclusion that it was the only wire on that whole circuit (it went to an external floodlight) so I flipped on that breaker, climbed the ladder, and crossed the wires. POP. Went back inside and checked which breaker had flipped. (Because I can't reach the wires with a multimeter safely.) So with it off I could cut the wire down lower, wrap the end with tape, and ...