Rosetta’s comet 67P, chasing for the last decade, now stinks—literally, scientists say.

If you smell the cloud of gas surrounding the icy nucleus of comet 67P/Churyumov-Gerasimenko you would smell a pungent mix of hydrogen sulfide (rotten eggs); ammonia (horse stable); and formaldehyde, researchers from the Bern Univeristy, Switzerland said.

The scientists told, there would also be a hint of vinegar (sulfur dioxide) and a smell of alcohol (methanol). Carbon di-sulfide would add just a touch of sweetness. In all, eau du Churyumov-Gerasimenko would be pretty horrid.

The two mass spectrometers were used by the researchers in Rosetta’s ROSINA instrument to determine what the comet would smell like. The spectrometers allowed the team to see the chemistry in the gas cloud, or coma, around the comet’s nucleus.

Carey Lisse, a scientist at Johns Hopkins University, who was not involved in the research stated, “In Churumov-Gerasimenko’s defense, most comets probably have a similar smell. In general, you don’t want to breathe in comets.”

“They are mostly water, but they also have a lot of primitive organics that might smell like the La Brea tar pits.”

The researchers were surprised to find so many different types of molecular materials in the comet’s coma, particularly because it is still three times the distance from the sun as the Earth. Moreover, as the comet moves closer to the sun, more gases will be released, and the comet will smell even worse, the researchers expects.