A satellite is a subviral agent composed of nucleic acid that depends on the co-infection of a host cell with a helper or master virus for its replication. When a satellite encodes the coat protein in which its nucleic acid is encapsidated it is referred to as a satellite virus. A satellite virus of mamavirus that inhibits the replication of its host has been termed a virophage. However, the usage of this term remains controversial due to the lack of fundamental differences between virophages and classical satellite viruses.