Does this work with the Wii U?
I am wondering if this works as an external hard drive for the Wii U to increase storage capacity.
Yes. But you need an adapter cord to have the WiiU power the hard drive.
dual A to Micro-B USB 3.0 Y Cable, Black
It splits it into two USB plugs that will plug into the WIiU which has 4 USB ports. So it would take 2 of the 4 spots.