Nimbuchaos

Nimbuchaos split from both it's ancestors when a stratonimbus mutated to have only six "feathers" and fell down to the planet. It was then devoured by a four-limb saganchaos, which, like it's ancestor did many times before it, absorbed the nucleus of the stratonimbus and fused it with one of it's own. After a long time of odd mutations and multiple deaths, it evolved into something much more complex than either of it's ancestors. It has evolved to have the saganchaos' membrane surrounding the stratonimbus' membrane, holding in a bubble of hydrogen produced from water in the air, which it uses to float, but not too high due to it's thicker limbs. The little limbs of the "feathers" now grow on the outer membrane, as they would be useless in the inner one. It now has five nuclei, which it uses in reproduction by simply splitting into five seperate cells, each with their own bubble. It now not only feeds on photosynthesis, but also eats sailcells whenever it can. It still absorbs ultraviolet light like stratonimbus, but appears blue due to warping of light in the outer membrane.