Virotophytes are hypothetical organisms proposed by biologist Thomas Cavalier-Smith as a potential fourth domain of life, alongside bacteria, archaea, and eukaryotes. These organisms are postulated to be a unique group of viruses that have evolved complex cellular structures and capabilities, blurring the line between viruses and cellular life forms. While virotophytes have not been definitively proven to exist, their proposal challenges our understanding of the diversity and evolution of life on Earth.