Wario's & Waluigi's eyes

[Yikes Spike]

Not important but interesting:
http://waluigiwatch.tumblr.com/post/124500100751/i-got-bored-and-made-this-a-theory-of-the-blue

 

[JoeKarta]

That's amazing! They really went all out with designing Wario and Waluigi.

 

[OriginalName244]

Finally, we have an answer for the mysterious blue eye-ring. Life's greatest question has been answered.

If it's not true, then meh.