This is a simple and quick way to create a cool halftone vector in Illustrator then edit it with Envelope Distort and the Bloat, Pucker, Twirl, Scallop, Wrinkle and Warp tools.
Create a rectangle and fill it with a black to white gradient in the Swatches Panel.
Choose Window > Gradient to pen the Gradient Panel. Click on the black color stop to open the swatch panel and choose 90% gray. Having the gradient go to black will create a hard edge at the end of the gradient once it is turned into a halftone.
Choose Effect > Pixelate > Color Halftone. Since the gradient is black and white, the angle will not make a difference. Set the radius to 20. A lower numbered radius will create odd shapes when the halftone is created.
This will create a halftone effect.
To trace the effect and turn it into a vector, it has to be Rasterized first. Choose Object > Rasterize. Set the Color Mode to grayscale, resolution to Custom and 600 ppi and Background to Transparent. Click OK.
A larger rasterized file will give you this warning. It may take a bit of time to process the halftone as an image but will yield a better result.
Open the Image Trace Panel from the Window Menu. Set the Mode to Black and White. Threshold to 128 (the middle), Paths at 50%, Corners at 75%, Noise at 25% and click the IGNORE WHITE check box at the bottom.
In the Properties panel (top) or the Control Bar (bottom) click the Expand button to convert the traced image into a vector shape.
Add a color fill to the halftone.
To distort the halftone, choose Object > Envelope Distort > Make With Warp… Choose from a list of warp modes.
Adjusting the warp type and setting will result in some fascinating results.
To Edit the warp options, choose Object > Envelope Distort > Envelope Options…
There are several warp effects that can be used.
To further edit the halftone once you are done with the distort, choose Object > Envelope Distort > Expand. This will convert it back to an editable vector shape.
Choose from a list of Editing tools. Double-click on any of the tools to open the specific tool dialog box.
This is the Bloat Tool options. Set the size of the brush and the options.
Apply the specific edit tool (in this case the Bloat Tool) to the gradient to create interesting shapes.
The fun is limitless with the Envelope Distort features.