Has to be Osborn (no matter what Irfans says) or his father. But if it is his father then he has undergone some change kinda like a Gollum/Smeagal thing where he doesn't identify himself as Richard Parker which as far as I know isn't in the comics.
Makes more sense (if they do a Venom movie) to have both Osborn and Venom in the sequel. Venom as the main antagonist and Osborn as the is he/isn't he a bad guy kinda thing.
As for someone getting into the cell - Sandman could do it easy enough.
He will show a tie in with Green Goblin and a new link to Peter and his father suggesting that his studies might be partially responsible for Spiderman's powers as well as Osbornes transformation.
60°
Makes more sense (if they do a Venom movie) to have both Osborn and Venom in the sequel. Venom as the main antagonist and Osborn as the is he/isn't he a bad guy kinda thing.
As for someone getting into the cell - Sandman could do it easy enough.
people have suggested Electro, as just as the guy appears there's a bolt of lightning, and as he vanishes.
though that could be a red herring.
He will show a tie in with Green Goblin and a new link to Peter and his father suggesting that his studies might be partially responsible for Spiderman's powers as well as Osbornes transformation.