As you may know, the Black Mesa incident had catastrophic and unforeseen consequences, including the apparition of portal storms which they brought several xenian elements such as Gastropolypus toxophlegmata (Bullsquids) or Sonicanis myriops (Houndeyes), and most importantly, the tools for the Combine to conquer us, something that in this case never happened.
The aftermath of these portal storms, which we suppose that ended at some point after a long time, leaves us with a big mess on every aspect of our lives. The xenians would adapt to the earth's ecosystem, with a small chance to even merge with our animals. By the time we would habituate to the xen elements.
I hope this answers your question. It's a very interesting and large scenario but I don't want to explain it on a forum post.
(Part 1)
Assuming the portal storms weren't ended by the Combine themselves and instead ended naturally, most of the xenian fauna and flora would have relocated to Earth and taken over the ecosystem. I have come up with some scenarios for individual species.
Vortigaunts: Without their master, they would have rebelled and freed themselves. Eventually, humans would contact and befriend them, though maybe it wouldn't be Eli Vance.
Alien Grunts: They are said to be fearless, to a detrimental point actually. They would just fuck around and find out, though their extinction wouldn't be as fast as under the Combine's reign.
Alien Controllers: Maybe they would be more cautious, but we really don't have info on them. Maybe they would go extinct without the grunts, but they sure as hell aren't defenseless.
Alien Crafts: Same as the rest of the Nihilanth’s army.
Hivehands: Barely even a creature, but they are indeed sentient. Yeah, I've got nothing, they would probably just die without the Grunts.
Leeches: They would quickly take over most oceanic ecosystems, quickly multiplying and tearing prey to shreds in seconds (they can easily destroy an HEV suit of all things). We do know seagulls eat leeches, and maybe other seabirds too, but I doubt that would be enough to keep their numbers in check. Maybe they would even hurt populations of Xenian Ichthyosaurs, which leads me to my next point:
Ichthyosaur: Ichthyosaurs wouldn't spread as rapidly, mostly living in lakes or rivers that wouldn't have been taken over by the Leeches. (Imagine being on the beach that fateful day and going for a dive, only for a recently teleported Ichthyosaur to devour you whole. Gnarly stuff).
Barnacles: They would likely take over abandoned areas without human contact, since most aliens are too stupid or physically incapable of looking up. (Fun fact, they use spores to reproduce. The spores probably don’t harm people though).
(Part 2)
Bullsquids: They would be hunted for their meat, given that they are big and plentiful. In remote areas though, one or two may dominate with some difficulty (they aren’t really social creatures). They may or may not live in sewers. They prefer easy food over living prey, perhaps they could be domesticated.
Houndeyes: Again, abandoned areas would have a lot of Houndeye packs, and also again, they would be hunted for their meat. Perhaps they could be domesticated too, but I’m not too sure.
Protozoans: They are fragile little things, the sharp debris would likely end any unlucky straggler. But we don’t know enough about them to make assumptions.
Gargantua: If one were to end up in a forest, you could say bye to all the trees. They are ridiculously resistant, maybe even leeches wouldn’t be able to pierce their armor. They would also need a lot of sustenance, and I don’t think they’ll be eating their veggies.
Headcrabs: Headcrabs in general would thrive in sewers, caves, abandoned buildings and other dark spaces where they are hard to see. Lightning Dogs would likely inhabit areas where plenty of Zombies have died. Gonomes would maybe roam the streets, and all kinds of Zombies too. Gonarchs would likely live in open caves or other large but protected spaces that would provide sustenance and shelter for both them and their 6900000 children.
Antlions: About exactly the same, but to a higher degree.
Boids: Assuming these things are carnivores, they would probably prey on Headcrabs and other small animals.
Snarks: Snark nests would be found all throughout the planet, terrorizing anyone or anything that came next to their nest.
Tentacles: They would reside in open mines and missile siloes, or big pits really. We have seen baby Tentacles reside in plant pots but those will probably die as they grow larger.
Bug: Remember those weird bug things in that one Xen cave? Yeah, neither do I.
Chumtoad: They would be at the very bottom of the food chain. Poor things.
(Part 2+1)
Clams: Those weird snappy things from Alyx would be found in small clusters, preying on insects.
Jeff Fungi, Spores, Hairs and other flora (even though fungi aren’t really “flora“ but just roll with me here.): They would exist everywhere, spreading to hosts if they can or just spreading everywhere.
Bloaters: Spreading from Zombie to Zombie, exploding whenever anything got close and spreading their spores.
Thanks for coming to my TED Talk I guess, let’s see if LambdaGen has a character limit or not (it does). I typed this out in Word before posting it here and had to split it into 4-1 parts because of the nasty character limit.
As you may know, the Black Mesa incident had catastrophic and unforeseen consequences, including the apparition of portal storms which they brought several xenian elements such as Gastropolypus toxophlegmata (Bullsquids) or Sonicanis myriops (Houndeyes), and most importantly, the tools for the Combine to conquer us, something that in this case never happened. The aftermath of these portal storms, which we suppose that ended at some point after a long time, leaves us with a big mess on every aspect of our lives. The xenians would adapt to the earth's ecosystem, with a small chance to even merge with our animals. By the time we would habituate to the xen elements. I hope this answers your question. It's a very interesting and large scenario but I don't want to explain it on a forum post.
absolute cinema !
(Part 1) Assuming the portal storms weren't ended by the Combine themselves and instead ended naturally, most of the xenian fauna and flora would have relocated to Earth and taken over the ecosystem. I have come up with some scenarios for individual species. Vortigaunts: Without their master, they would have rebelled and freed themselves. Eventually, humans would contact and befriend them, though maybe it wouldn't be Eli Vance. Alien Grunts: They are said to be fearless, to a detrimental point actually. They would just fuck around and find out, though their extinction wouldn't be as fast as under the Combine's reign. Alien Controllers: Maybe they would be more cautious, but we really don't have info on them. Maybe they would go extinct without the grunts, but they sure as hell aren't defenseless. Alien Crafts: Same as the rest of the Nihilanth’s army. Hivehands: Barely even a creature, but they are indeed sentient. Yeah, I've got nothing, they would probably just die without the Grunts. Leeches: They would quickly take over most oceanic ecosystems, quickly multiplying and tearing prey to shreds in seconds (they can easily destroy an HEV suit of all things). We do know seagulls eat leeches, and maybe other seabirds too, but I doubt that would be enough to keep their numbers in check. Maybe they would even hurt populations of Xenian Ichthyosaurs, which leads me to my next point: Ichthyosaur: Ichthyosaurs wouldn't spread as rapidly, mostly living in lakes or rivers that wouldn't have been taken over by the Leeches. (Imagine being on the beach that fateful day and going for a dive, only for a recently teleported Ichthyosaur to devour you whole. Gnarly stuff). Barnacles: They would likely take over abandoned areas without human contact, since most aliens are too stupid or physically incapable of looking up. (Fun fact, they use spores to reproduce. The spores probably don’t harm people though).
(Part 2) Bullsquids: They would be hunted for their meat, given that they are big and plentiful. In remote areas though, one or two may dominate with some difficulty (they aren’t really social creatures). They may or may not live in sewers. They prefer easy food over living prey, perhaps they could be domesticated. Houndeyes: Again, abandoned areas would have a lot of Houndeye packs, and also again, they would be hunted for their meat. Perhaps they could be domesticated too, but I’m not too sure. Protozoans: They are fragile little things, the sharp debris would likely end any unlucky straggler. But we don’t know enough about them to make assumptions. Gargantua: If one were to end up in a forest, you could say bye to all the trees. They are ridiculously resistant, maybe even leeches wouldn’t be able to pierce their armor. They would also need a lot of sustenance, and I don’t think they’ll be eating their veggies. Headcrabs: Headcrabs in general would thrive in sewers, caves, abandoned buildings and other dark spaces where they are hard to see. Lightning Dogs would likely inhabit areas where plenty of Zombies have died. Gonomes would maybe roam the streets, and all kinds of Zombies too. Gonarchs would likely live in open caves or other large but protected spaces that would provide sustenance and shelter for both them and their 6900000 children. Antlions: About exactly the same, but to a higher degree. Boids: Assuming these things are carnivores, they would probably prey on Headcrabs and other small animals. Snarks: Snark nests would be found all throughout the planet, terrorizing anyone or anything that came next to their nest. Tentacles: They would reside in open mines and missile siloes, or big pits really. We have seen baby Tentacles reside in plant pots but those will probably die as they grow larger. Bug: Remember those weird bug things in that one Xen cave? Yeah, neither do I. Chumtoad: They would be at the very bottom of the food chain. Poor things.
(Part 2+1) Clams: Those weird snappy things from Alyx would be found in small clusters, preying on insects. Jeff Fungi, Spores, Hairs and other flora (even though fungi aren’t really “flora“ but just roll with me here.): They would exist everywhere, spreading to hosts if they can or just spreading everywhere. Bloaters: Spreading from Zombie to Zombie, exploding whenever anything got close and spreading their spores. Thanks for coming to my TED Talk I guess, let’s see if LambdaGen has a character limit or not (it does). I typed this out in Word before posting it here and had to split it into 4-1 parts because of the nasty character limit.