Here's how I usually describe what a migraine aura looks like:

It's just like the after-image you see after glancing directly at a bright light (like a light bulb's filament) then looking away or closing your eyes. Now imaging that after-image with a colorful scintillation along the edges, sometimes wrapping around a blind spot in your vision (not necessarily a black spot).

The cilia of a lobed comb jelly are close to what I'm talking about (video: https://youtu.be/LPu1juezWeg)

Auras are beautiful little harbingers of debilitation.