If something on Earth was "... suffused by huge amounts of gas that can reach scorching temperatures up to 100 million degrees Celsius" it would be described as a plasma, the purview of plasma physicists and electrical engineers. They would potentially link the phenomenon with the associated magnetic and electric fields that contain and maintain that plasma.
What would it mean for theoretical cosmologists? With every observation being attempted to be explained by gravity-only models (yeah dark matter, I'm talking to you), they begin to seem like the man with a hammer, for whom everything is a nail. Well, screw that...