Space: 1999: S2 E4 - All That Glisters Space: 1999

The Alpha Moonbase needs a rare ore known as Milgonite, which is detected on an extremely dry planet. Koenig leads a small landing force and discovers a glowing rock formation which comes alive and cuts off the party's links with the base. It is a trap - the planet needs water to survive and has lured the travellers there for the water in their bodies.