Speedometer fluctuating - can't find this issue on any forum

I've spent hours and hours googling this, I can't find anyone who's ever posted a similar situation. There is no issue with the display turning off, flickering, etc. The only issue is that SOMETIMES the speedometer keeps WILDLY fluctuating. We're talking a random number every .025 seconds. Sometimes it does it, sometimes it doesn't.

It only does it when the vehicle is moving, not while in park.

I have uploaded a really bad (sorry) video, you can see in the beginning of the video the speedometer wildly fluctuating, but as the brakes are applied later in the video the speedometer returns to normal.

Super frustrating that I can't find anyone else with this issue and the Toyota dealership is telling me it's $160 just to test.

2010 Prius (not sure if I II or III), with ~95k miles.

Also the 12v battery was already replaced within the last 12 months.

Appreciate any help.

Apparently the post auto deletes links so here is the **IMGUR LINK WITH VIDEO** i m g u r d o t com/a/P7T2o

 

cool i can guarantee since i live in NoVA it's going to be like $1k taking it to the dealer.

 

as an update my wife was driving the prius today and for a while it just read either 1mph with most of the dash lights off or 188mph with all of the dash lights on...everything, the mph, km/h, all park/drive stances, lol what is going on