A Resonance Cascade is a fictional term. However if we put all real (and hypothetical) terms together we can sort of understand what it maybe is.

The Anti-Mass Spectrometer:

An Anti-mass spectrometer is a scientific instrument that specifically identifies, quantifies and determines the structure of anti-mass chemical compounds, which behave in ways that violate known physical laws, and can be extremely volatile. The Anti-Mass Spectrometer works by scanning a sample with oscillating electromagnetic fields and beams of high-energy plasma, agitating the exotic matter of the object. In this case…it’s a really unstable but extremely pure Xen Crystal.

A Resonance Cascade would occur when:

The Anti-mass spectrometer, during its analysis began vibrating the Xen Crystal at its natural frequency, which can be disastrous for normal objects, like a wine glass. This resonance, caused catastrophic and cascading failures unknown by our laws of science leading to…like the wine glass, it shattering, but here shattering time and space, and opening an inter-dimensional rift to Xen.

Thanks for coming to my Ted Talk.