As a quick summary, at page 15, what I can gather from what Morton is saying is that a Hyperobject is anything which is beyond a humanly scale. This can include things like the weather, a mountain, the internet, conciousness, etc. At this scale “objects” take of aspects of phenomena. Phenomena are things which are somewhat contentious in rational, scientific thought. So a Hyperobject is somewhere between science and fiction. Morton brings up the chasm between phenomena and thing a number of times, and this divide/connection as a complication in philosophical and scientific thought.
I think Morton, by looking at Hyperobjects and Object Oriented Ontology (OOO), he is bringing the human, and in particular all the things which have been seen as specifically and specially human (like thought, conciousness, emotion etc.) all back down onto the same level as objects; stuff; things; which make up the real world around us.
I think this is exactly why the term Hyperobject is used. These super-human notions of complexity beyond the realm of human scale, are in fact objects, like everything else we exist alongside. It is the taming of the phenomena.