Q:

How to create warped ripple/wave effect?

I'n trying to recreate an effect similar to the background of this post on Dribbble:

I don't even really know what to call this effect, but it reminds me of the Twilight Zone and old black and white sci-fi. I know how to warp lines, but not sure how to get the random width variation, etc. 
Bonus points for describing how to create this effect generatively in code (using something like p5.js or Processing).

A:

Using Illustrator
From a line pattern and using those transforming tools, 

with patient and time it is possible to get something similar (better than the one I did to show the process):

Drawing a profile with the Pencil Tool, put it over a rectangle and use the Shape Builder Tool to get the other profile:

Use a background image to make a Transparency Mask on each profile and get the rough surface:

Change the profiles blend mode to Multiply

Result

SVG:
https://codepen.io/danielillo/full/PBOgNa

A:

The pattern is reminiscent of Japanese marbling (Suminagashi), such as the image below.  It's essentially made by repeatedly dropping ink, and detergent, onto the surface of water using two brushes, then a print is taken by placing a sheet of paper onto the surface of the water
.
However the example you posted looks as if it has been created by drawing it by hand. It doesn't look like it has been generated automatically.  Almost any vecotor image editing software such as Inkscape, Illustrator, CorelDraw, Sketch, etc, could be used to recreate something like that. Inkscape and Illustrator certainly have warping tools which could be used to distort horizontal stripes similarly, not so sure about the others. The rest is simply overlaid vector shapes.
Another possibility is using Adobe Photoshop, which has a Liquify tool which could be used to create similar shapes from simple horizontal stripes. Or if you don't have access to Photoshop, then GIMP has a similar Warp Transform tool. The result could be easily auto traced in vector software.
This is an example of the Liquify tool in Photoshop.

Sorry, I can't give you any code for doing this. I'm no programmer.

