

One more idea, this time in 3d:
- Create an icosphere with maybe 6 subdivisions
- select just one vertex
- Use the same random proportional editing tool to randomize the surface radiating away from the selected vertex
- Set a material and use a diffuse black shader
As a bonus, you can have the object rotate to give it an animated, portal-like look.
I felt like a wizard as a kid because I knew how to defrag the hard drive and degauss the CRT.