The first gameplay reveal of Spider-Man 2 took place recently, and it showed off Peter Parker in the black suit as he made quick work of Kraven's goons. The demo followed him and Miles Morales as they raced across the New York Bay to save Dr. Curt Connors, who has turned into the Lizard at this point, from Kraven.
The gameplay for Spider-Man 2 did reveal exactly how the symbiote might work within the game's universe, and it looks like Insomniac might be taking some heavy inspiration from the Ultimate Spider-Man comics by Brian Michael Bendis.
Spider-Man 2's symbiote origins might be heavily inspired by the Ultimate Spider-Man comics
In the main 616 Marvel universe, the symbiote is an alien and gooey substance that hails from outer space. The basic premise behind it is that when attached to a host, the symbiote can basically increase the strength of a person and even influence their nature, which is a big part of Spider-Man's history.
However, in the Ultimate Spider-Man comics, writer Brian Michael Bendis took a different route. He reinvented the origins here, and rather than making it an alien substance, he made the symbiote a form of medicine that was created by Peter Parker and Eddie Brock's father. The basic idea here is that when attached to a host, the symbiote can cure any disease while also making the person strong.
In the comics, Peter Parker of course receives the symbiote but learns of its disadvantages, and then the symbiote goes on to attach to Eddie Brock Jr., who at that point would be mad that Peter broke his trust and used the symbiote and would become Venom. So, it looks like Spider-Man 2 might be going the medicinal route with its origins in the symbiote because of the way it has been set up.
In the first game's post-credits scene, we get to see that Harry Osborn is sick and that the symbiote has been attached to him in order to keep him alive and has even bonded with him. Then in Miles Morales, we get to see that Dr. Curt Connors is the one who has been treating Harry with thesymbiote,e teasing the fact that he might have developed it. And then finally, in Spider-Man 2's gameplay, we hear that Harry is sick and that Connor's help is needed.
So, if anything, we can expect the symbiote to be a man-made creation in the game rather than an alien entity; however, the question remains who Venom might be in Spider-Man 2. The first game heavily hinted at it being Harry Osborn, but since in the Ultimate Spider-Man comics Eddie Brock interned under Curt Connors, there is a good chance that we might see him become the monstrosity in the game as well, considering he is confirmed to be a part of the game universe.
Whatever it may be, though, our questions will soon be answered once Spider-Man 2 releases for the PlayStation 5 console this fall.