True Psionic ascension/assimilation for singe race?

[Willy Waggler]

Synthetics have their assimilation, bionics have necroids(though heavily loaded), but what about psionics? They can "assimilate" but that just giving trait and is quite underwhelming.
What about last perk giving ability to "ascend" into energy beings like ancients/ori in stargate?

 

[rubert]

What sort of interesting gameplay that would involve, as I assume you don't want it to be a victory button where your empire ascends to a higher plane of existance and goes poof from the game?

 

[Willy Waggler]

What sort of interesting gameplay that would involve, as I assume you don't want it to be a victory button where your empire ascends to a higher plane of existance and goes poof from the game?

Turn your race into unique species that can't procreate or be modified in any way, but come with unique trait(s) that you can choose during ascension(like what pact you can pick with shroud)
And then you can help lesser species with ascension into your new race. Something like that.