This is a double or triple exposure. They took the picture of the bassist with flash, and then found some lights maybe above the stage, set the shutter to a slow speed maybe like 1/2 or 1 second, no flash, probably turned up the aperture so only the brightest lights are getting in, and then took a picture of the lights while rotating the camera, which overlays on top of the original.
This can also be done in post but often is a lot more annoying to do then rather than just being creative in the moment. Double exposures are super fun, especially for live music. Take note that not every digital camera will give you the option to do this.
This is a double or triple exposure. They took the picture of the bassist with flash, and then found some lights maybe above the stage, set the shutter to a slow speed maybe like 1/2 or 1 second, no flash, probably turned up the aperture so only the brightest lights are getting in, and then took a picture of the lights while rotating the camera, which overlays on top of the original.
This can also be done in post but often is a lot more annoying to do then rather than just being creative in the moment. Double exposures are super fun, especially for live music. Take note that not every digital camera will give you the option to do this.