Perhaps light is like a plasma, something that has a dual character. When observed from beneath the speed of light (by an observer who is more dense), it displays characteristics of energy. When observed from above the speed of light (by an observer who is more diffuse), it displays characteristics of matter.
In these models, the speed of light functions like a 2D membrane or fabric. Squeeze it intensely, make it smaller than itself by a full degree (see the fourth state of matter experiment), and it generates c. Stretch it intensely, make it larger than itself by a full degree, and it requires c.
Electricity and magnetism are twin halves of the same force—electromagnetism. At the speed of light, they are held in balance. Perhaps when light is dramatically squeezed, electricity emerges. And when light is dramatically stretched, gravity emerges.
