Ouch, Hopefully its internal structures don't collapse. I love contrasting proportions and this is certainly an interesting organism. Just one question is it releasing water vapor through the holes in its "head"?
So it was genetically engineered in a sense but also using some inorganic methods of creation, by a much higher intelligence than that of the human race. The picture looks amazing i love how you put the large "head" in the midground and then the tendrils wrapping around the background, looks really good.
I personally can't think of too many fictional organisms larger than this. THe only ones that come to mind are Any Deep Hunter soace bound organisms, scp-169, andafew other space bound cratures. It may sound like a lot, but there are millions smaller. ANyways, I love this