Pym particle

Tissue Compression Eliminators killed by firing a modulated beam of gravitons and Pym particles which drastically compressing the bodies of its targets to the point where life functions ceased. (PROSE: The Quantum Archangel)

Behind the scenes
Pym particles are likely a reference to Marvel Comics. In the Marvel universe Pym particles are a group of subatomic particles isolated by Dr, Henry Pym, who uses devices based on that discovery to alter his size as the superhero Ant Man.