Severe acute respiratory syndrome coronavirus 2
The genetic material of this virus showed many similarities to SARS-CoV (79.5%) and bat coronaviruses (96%). This means the virus may have originally come from bats. Scientists did more experiments that showed the virus probably went from bats to an intermediate host, meaning another animal in between bats and humans.  The viruses in that other animal changed over time until they could infect humans.  Scientists are close to sure that the original animal was a bat but not sure what the intermediate animal was.  Some scientists think it could have been a pangolin because there are coronaviruses that live in pangolins even though they are not exactly the same as SARS-CoV-2 or the ones in bats.  Pangolins are an endangered species and buying, selling or moving them from place to place is illegal in China and many other countries.  But their scales are an ingredient in many traditional Chinese medicines, so they are often sold on the black market.