It kind of looks like a fluids cloud, but its not as theres the geo there,
I might have a guess that its been imported from something like Vue as theres some serious texturing going on with bumps/displacements etc etc that would have been brought over with the low level geo from something like Vue.
If you have a look in the Visor theres an example of a nebula using fluids that looks similar when you render it
"No pressure, no diamonds" Thomas Carlyle