hmmm incorporeal aliens? interesting...
not energy beings but (going trek for a min) EM coalesced gaseous forms... able to alter the gas like "body" to different shapes and solidity the more solid the less movement and speed and the more weight
weakness would be reversed polarity EM fields or what ever.
didnt work lol i wanted to try and make a cloud like model, make it transparent with a nebula effect and then have that texture animate as if the cloud was moving about.
i got working : model, transparency, nebula like cloud effect also transparent and thats it...
i tried using the animated tutorial by cordanilus and on my version of nifscope it wont let me alter the Niflip controller, the "target" text line was greyed out

hmm: also i just realised that when you shoot the "cloud" ship it will be damaged as per the damage texture... so on mine you'd have hull damage with sparking and flames... not really what youd see on cloud vessel lol.
back to drawing board again lol