A group of single-celled eukaryotes, also called Mesomycetozoea or Ichthyosporea, that live chiefly as parasites of fish and other aquatic animals. The acronym derives from the initial letters of the names of the four genera known to the discoverers of the group: Dermocystidium, ‘Rosette agent’ (now given the formal taxonomic name Sphaerothecum destruens), Ichthyophonus, and Psorospermium. The group includes several commercially important parasites and the causative agent (Rhinosporidium seeberi) of the human disease rhinosporidiosis, which affects the nose. Molecular systematics shows DRIPs to be among the closest single-celled relatives of the animals, forming a branch in the phylogenetic tree near to the divergence of fungi and animals.