Need advice about a "invalid disc" error

I just picked up Splatoon used from Goodwill for $20. It just caught my eye and I thought it was a great price so I grabbed it.

Get home and the disc isn't working at all. I googled pictures of it and it looks legit, and it doesn't appear scratched up at all.

This is the first disc I've ever tried on my WiiU, so it could be the system--I've only played digital Mario Kart so far.

I don't know anyone with a WiiU to try this on, and I don't have any WiiU discs to figure out if it is the system!

Any advice?