Never seen one of these?

To my amazement I watched this short video on Twitter and saw a tool that I never saw before. It is a Makita grooving tool used by timber workers. Kind of like a power plane with a dado blade in it.
Just when I thought I’ve seen it all. Go figure. Eh.
Here is the link to the video and a pic of the tool to.

http://thecarpentryway.blogspot.ca/2015/02/gateway-48.html