Farscape S02 E02 Vitas Mortis

"My name is John Crichton, an astronaut. I'm just looking for a way home."

D'Argo takes part in a sacred ritual that helps an old Luxan, an Orican, to survive. During the ritual the Orican draws energy from who she thinks is D'Argo but is actually Moya. Consequently Moya starts to age rapidly.