The skeletal horse trap was added in 1.9. It would have turned into the four horsemen of the apocalypse. So, unless the server was modded, it wouldn't have been ten skeletons.
It wasn't too bad, but it wasn't very exciting either. Definitely look at some other way to capture the video outside of the tablet.
Just make sure that you go into the recording with a plan for what you want to accomplish. Also, if you promise a release schedule, stick to it. This was the only video in the playlist and it has been over a month since that was published.
I've subscribed. I'm looking forward to seeing what else you can do with this series.