In 2370, Doctor Mora Pol of the Bajoran Institute of Science mounted an expedition with Starfleet assistance to L-S VI, where probes had discovered DNA similar to Odo's. Silicate-based lifeforms were found on the planet, including a small vegetative organism with Changeling-like metamorphic properties.
During the expedition, Jadzia Dax, Mora Pol, and Weld Ram were injured from inhaling a ground eruption of volcanic gas. Odo was also unknowingly affected by the gas, which caused him to change into a large, instinct-driven creature back aboard Deep Space 9. (DS9: "The Alternate")