On a more serious note, it would be rather interesting/cool to have certain planets or even a singular planet to have Dragon like alien lifeforms with the visual appearances of celestial or oriental dragons. Throw in a few alien tribes who worship them as God's and we have ourselves a side quest or a main story quest(but only if we get to ride one into battle at the end of the game).
They could be a cosmic migrating species, every 100 or 1000 years they come to a specific planet from all over andromeda. A nest persay that due to unknown planetary reasons only becomes viable once every 100/1000 years. By traversing the cosmos like a quarian does during their pilgrimage they acquire knowledge, wisdom, experience, adventures all in all only to return to the very place they were born. Where upon returning they mate, rest, then perish by becoming one with the nest making it larger and larger each time.
They could hold a role specific to andromeda, their existence could be like a galactus of sorts where by breeding & dying continuously for hundreds and thousands of years on a single planet their nest eventually becomes THE planet where then only one "dragon" is born. A special one. Named Atreyu, a single male with the collective knowledge of his species and the planet's(including all life on now dead planet). This special dragon would be unto andromeda what the reapers were to the milky way.
It'd be a never-ending story.