A mysterious stink wafted through Toronto’s downtown core on Tuesday morning. The first official reports of the stench came in around 8.30 a.m. after a person called emergency officials to complain of a “dead animal” smell wafting just west of Union Station, the Toronto Star reports. Firefighters and the Toronto Transit Commission have responded, but didn’t find a dead animal or a gas leak. The city is also looking into the source of the stench, with investigators out hunting for an answer. Some have said it smells like an outhouse, while others describe it as egg and sewage mixed together. Twitter users are guessing at the source of the stench, many of them with saucy answers relating to the current election, under the hash tag #whatsthatsmell.