The Zybourne Clock is a device located near Skylord Jasper's Retreat. Its function is currently unknown, except that it shows time as a clock normally would. There are multiple signs saying:
"A shameful path led us here... this my darling is a device"
"A device many men and many women have died to see, to understand, and to own."
"In many ways it is like many of your toys, but a toy for adults. This my darling.....is the Zybourne clock."
These signs are also on the edge of steps leading up to a chest. The chest is empty but the steps leading up to the chest are in fact the sides to a five of spades playing card. This could just be a random feature, or a reference to the game or something to do with the clock itself.
This may be in fact a time machine, referencing to the failed video game attempt "The Zybourne Clock". The theory and basis of the game used four red balls on a cliff with the statement "time works the same way." These features may also be sundials.
The clock has never been featured or even acknowledged in any video, and it is unknown whether it will be shown in future episodes of the series.