In "The Crystals," the second season episode of Buck Rogers in the 25th Century, Buck, Wilma and Hawk must find more thurbidian crystals to power their ship.

The trio lands on a planet, Phibocetes, thought to be uninhabited. But what kind of sci-fi show would it be if there weren't a few aliens to contend with?

They first discover what they call a "mummy" buried in the planet's dirt. Then Buck meets a young girl who doesn't know who she is or where she came from. While the planet yields plenty of thurbidian crystals, the mummy they thought was long dead comes to life and escapes!

Wilma analyzes blood left behind by the creature and compares it to a blood sample taken from the girl, who they name Laura. What she discovers shocks both her and Buck. The two samples are exactly alike, a perfect genetic match. They reason there must be a connection between Laura and the violent humanoid they discovered first.

But a ferocious space mummy isn't the only thing identical to Laura's blood.

A quick microscopic glimpse of her blood on the analyzer screen shows a blue and green crystalline structure. Seventies sci-fi fans can instantly recognize it as not just alien blood but a deadly extraterrestrial organism in itself.

That's right, the sample shown in Buck Rogers is the same graphic used in The Andromeda Strain.

The 1971 thriller, based on Michael Crichton's best-selling novel, follows a group of scientists who investigate a deadly organism that fell from space and starts to wreak havoc on earth. In a pivotal scene, they discover that Andromeda's "crystalline structure" is key to its survival.

Whether intended as a deliberate reference, or just simply a way to save money by recycling footage, the presence of the organism from The Andromeda Strain in Buck Rogers in the 25th Century is fun easter egg for any classic sci-fi fan.