I had a thread about these a long time ago, but it disappeared. Here's one Conners is working on a serum using lizard hormones which revert cells into an embryonic state so that they will regrow missing body parts. (by coincedence, in reality this research has been going on for a while now, but it will probably be abandoned in favor of embryonic stem cell research). He develops a serum which when it comes into contact with living cells it incorporates some of that host's DNA into it's own, sort of like the way a virus works, and starts replicating a lot of this genetic material, which is in an embryonic state, so that it can regrow missing body parts. But everytime he tests it on rats it causes other cells to revert back to an embryonic state in a cancerous lump. Peter is one of his lab assistants. Spider-Man gets into a battle with the Sandman and he is beaten severely, smashed shoulder, smashed everything. He stumbles to a cab, says hey take me to this address(its an address nearby where he lives) when he gets there he stumbles out of the cab and falls. The driver says dont worry about the tab and drives off. MJ looks out their window and sees him laying there and rushes out to him and says shes getting him to a hospital, he says no because of his secret identity. So she brings him to Conners. Conners injects him with the serum. He wakes up next day good as new. Next day there is a lump in his side, so he goes to see Conners. Conners decides to remove it. He removes it and sticks it in a jar with fluid, and says hes going to study it, to help him with his research. Pete shows up to work for Conners the next day and Conners, not knowing that pete is spidey, tells him what happened. They decide to run some tests on it, and Conners pokes it with a sharp needle, and when he goes to poke it a second time it forms a small skinny tendril two or 3 inches long which breaks the syringe. Conners finds that heat or high pitched frequencies cause it to lie dormant, making it easier for Conners to run tests on it. During the tests on the lump, they find that its in an embryonic state, so Conners puts it in some amniotic fluid, to see what will happen over the next few days. Over the next few days, the cancerous lump grows into a black liquid, consuming all of the amniotic fluid, untill it breaks out of the jar, and wala, you have a symbiote, capable of thought and emotion, containing the hormones of lizards, which causes its primary emotion to be anger(anger is the only emotion lizard brains are capable of inducing). So this symbiote has some anger problems, its got some of Spider-Mans DNA in it, and it experiences thought, and because of its DNA it can home in on Petes spidey sense and track him down, and bond with him. Since its a group of cells in an embryonic state it can regenerate tissue and it can generate tissue in whatevershape it wants, like clothing for example. It homes in on pete, bonds with him, spidey goes to conners to ask him what it is, and later down the road Conners discovers its the same cancerous tumour that he removed from him. It needs a host in order to survive. It feeds off of angry emotions, sweat, dead skin, and body heat, even though temperatures high enough to harm a human, harm it as well. Conners says that if Spidey doesnt get rid of the symbiote it will eventually take complete control of him, and recycle all of Spideys body into itself.