I just thought of something...
I don't know if any of you remember but a while ago I made a thread that talked about how in the spider-man 3 game apparantly Kassady saw Brock change into venom...I was thinking, when that bit of symbiote fell onto Brocks jacket and brock took of his jacket and threw it away, could that bit of symbiote left and bonded with Kassady? (if the whole him being in the game thing is true that is)