A team from the Mediterranean University of Marseille first discovered a virus infected by another virus in a cooling tower in Paris. The host is a giant virus that attacks amoebas -- they are gigantic viruses larger than some bacteria -- and the aggressor is a small virus with a genome that does not encode more than 21 proteins. Sputnik, which has been named virus, has defined the group of virophagi for classification (scientists have agreed that viruses that attack bacteria are more bacteriophages and that those that attack viruses are more rhetorical).