Hard Light

Explanation
Hard Light is an artificial substance first created by Spectrum in Resonance #2: Steel Soldier. Spectrum, being a light based resonance user, was able to create constructs in hard light that mimicked the properties of physical matter. His ability to create was virtually without limit and he personally built various UN.C. Headquarters.

Spectrum's Hard Light structures could also mimic unknown properties and perform tasks that baffled the minds of mathematicians across North America and Europe.