Festering Tarhole

Noun (origin- SW Ontario, Canada) -A geologic phenomenon indicated when crude oil seeps to the surface under subterranean pressure often forming large patches of thick tar and exhibiting the occasional appearance of bubbles at the seepage source. Some local First Nations people would collect and use this tar for various applications like water-proofing, adhesive, etc. It was also flammable, so that's fun.

The overwhelming stench of these tarholes was so great as to lure Captains of Industry who arrived to thoroughly exploit this relatively limited resource around what is now called Oil Springs, Ontario. Sulphur, brine water and decay smelled like money to these men. Rumour is that the "hard oilers" who worked the fields coined the phrase first, as a colourfully descriptive reference to the geo-phenom but the phrase gradually turned to a more derisive tone and was later more often used to refer to someone that was to be held in the greatest of disdain and worthy of social ire. You want to hit them but you can't afford the charges, kind of thing.