Microscopic lifeforms existing partly as matter and partly as energy, found in a plasma streamer and responsible for trapping a starship crew inside a transporter beam in Realm of Fear.
Quasi-energy microbes appear in the Next Generation episode Realm of Fear. They live in the plasma streamer running between the two stars of a binary system, which the science ship USS Yosemite was studying in 2369 when it fell silent.
The Enterprise finds the Yosemite damaged and several of its crew missing. Lieutenant Barclay, who dreads the transporter, forces himself to beam across and sees large worm-like shapes swimming in the matter stream, one of which touches his arm. He fears he is imagining things, but his arm begins to glow.
The microbes had infected the missing crew, who tried to filter them out by holding themselves in the beam and became stuck there. The shapes Barclay saw were the survivors. He seizes one in mid-transport and pulls a crewman free, and the others are recovered in the same way.