Warning, post credit scene spoiler in highlighted area. Answer to this question may contain spoilers too, so avert your eyes in case you haven't seen this movie yet.
In the post credits scene in The Amazing Spider-Man (2012),
Dr. Curt Connors (The Lizard) is in a jail cell. He has a conversation with someone. Who is this person or villain?
The script is something like:
(Dr. Conner is lead to his cell. There is lightning outside in the storm.)
Unknown man: Hello Doctor. Did you tell the boy?
Dr. Conner: Tell him what?
Unknown man: Did you tell the boy the truth about his father?
Dr. Conner: No.
Unknown man: Well, that's very good. We'll let him be for now.
Dr. Conner: You should leave him alone!
(Lightning strikes again in the storm. End scene.)