Strange resistor colours
Alright, I finally found something that supports Spehro Pefhany's proposal. This is a common 4 band resistor.
The black band is there because both 3 and 4 band resistors aren't required to use gold and silver on the readings. Thus, some resistors can be read backwards (Yikes).

To solve this, the black band is put onto the resistor to tell which way it's supposed to be read. Later, this was replaced by deliberately spacing the bands, but it seems that some manufacturers still use the black band.