An interesting feature of the Ghosts (UK) episode (Season 1, Episode 5) is its deep-cut connection to the sitcom Friends .

The title is the caveman ghost Robin's pronunciation of "Moon Stone".

When Julian describes the neighbor Barclay as being "richer than Crassus," it’s a meta-joke: Simon Farnaby (who plays the ghost Julian) famously played Crassus in the Horrible Histories series.

It is revealed that the grounds of Button House were once a sacred site that Stonehenge was actually copied from.

Are you interested in learning more about or other pop culture references hidden in the show? "Ghosts" Moonah Ston (TV Episode 2019) - IMDb