Barion radiation
Referenced in the first draft script of the  seventh season episode , barion radiation was a type of radiation that was used in the development of the morphogenic virus. Exposure to barion radiation could cause a Changeling's morphogenic enzymes to spike and could also mutate a  into a virus.

Julian Bashir and Miles O'Brien discovered, during the course of the script, that, at Starfleet Medical, Section 31 had used barion radiation to mutate a cell from Odo into the morphogenic virus that was now infecting him and the rest of the Founders.

See also
Baryon radiation
Unused production material