Virus
Virus is a micro-organism with a unique characteristics different from all other elements in universe. All things that we find surrounding us either living or non-living.
But virus is only a matter that have both two characteristics. Virus may found as living organ as well as non-living organ. When Virus is hosted by other living organ it react as living organ and causes significant harmful effect of hosts. When virus stays independently in nature it reacts as non-living organ.
Virus have a wide different from bacteria. It is several times smaller than bacteria. Virus can not destroy by antibiotics. A few antiviral drugs available to destroy virus. Vaccine is a traditional option to prevent viral infection.