All of a sudden today, my the mouse cursor started jumping to the exact same spot on the screen (near top-right) every second. I could move it for up to a second, but it would jump back.
I have a Logitech mouse. Unplugged it. Still does it.
Restarted computer. Still does it.
Tried Magic Mouse. Still does it.
Gaa!!!
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Found a forum post https://discussions.apple.com/thread/1829111?start=0&tstart=0
Someone mentioned Wacom tablet. Yes! I have a Bamboo Drawing Tablet on the side of my desk. Someone bumped the pen so it was setting on the tablet. Each second, it was moving to the position dictated by the pen on the tablet.
Moved the pen.
Everything works.
Hope someone finds this and saves them a headache or 3!
The Gahooa Perspective 
OMG! I was searching Google for the exact same baffling problem, and found your blog. After seeing your solution, I looked behind my Mac, and there it was! My Wacom pen had fallen against the tablet, causing the jumping mouse!
Hahahah!
Sheesh, I’d been pulling my hair out trying to figure it out. I was just getting ready to re-install the system software, but thought I’d fire up the laptop to search first!
Thanks for the solve and the laugh.
Hey Steve,
I’m glad this helped you. Feel free to link to this page to up the SEO if you have a good place to link from, as I’m sure we are not the only ones who got bitten by this “bug”.
Take care,
Jason