At the top of the entrance to the Hidden King's base is an invisible platform that can only be stood on if entered from the sides. Below I am providing a video showing how to reach it. In the video I am within the sandbox mode but I first discovered this during a regular match and can confirm it works there too.
I also checked the same place around the Archmother's base but couldn't find anything there.
I also checked the same place around the Archmother's base but couldn't find anything there.
