Solid monster story.
Extra points for not trying to explain what the thing was or where it came from, having an indeterminate ending and using a disabled character to good advantage. Also, plus points for the dog being neither hero nor villain, just a dog.
A few points lost for needing a little more editing - All that build-up, like an unimportant description of a picnic and a totally unnecessary sex scene, feels like padding when one reflects that the thing just shows up and attacks. Could have done with more tease from the actual threat. The description of the creature, while starting nicely pulpy, went a bit overboard in the florid writing area (did the author really intend to use the word "fecund", meaning overly fertile, to describe some aspect of the creature?) and where were the editors when the paralyzed man with the severed spinal column feels the dog pass over his ankles (the bit where the dog is biting his foot was good, although written in a way that we can't tell whether this was painful for him or just distracting, given the fact that's he's crawling after his wife).
I'm unsure about the Giger reference. Part of me thinks that any 19th century writer would just have easily referenced Bosch or someone and this is the modern equivalent of same. Part of me thinks that modern society, at least in America, is so culturally fractured that almost any reference to anything outside of the main-mainstream comes off as a bone thrown to a niche group. Undecided.
Nice monster story, though.
Thanks for listening.
“Demons are like obedient dogs; they come when they are called.”
Remy De Gourmont, “Pehor”