MAJOR SPOILER AHEAD!
What you are looking at is Norman Osborn's cryogenically frozen head!
As it was previously revealed, Norman (Chris Cooper) does die in The Amazing Spider-Man 2, with Harry Osborn (Dane DeHaan) taking on the mantle of Green Goblin. Norman has been afflicted by a mysterious illness that only Peter Parker's blood can cure. When Harry, working as Goblin, and Electro fail to obtain the mutant spider blood, Norman passes away, and Harry is sent off to Ravencroft. In the post-credit scene, we are once again introduced to The Man in the Shadows, from The Amazing Spider-Man's post-credit sequence. We see him walking up to the cryogenically frozen head as he whispers, 'Wake up old friend."
So, Norman is surely going to make a comeback in The Amazing Spider-Man 3. What do you think of this revelation? Sorry you looked?
The Amazing Spider-Man 2 was released May 2nd, 2014 and stars Andrew Garfield, Emma Stone, Jamie Foxx, Dane DeHaan, Colm Feore, Felicity Jones, Paul Giamatti, Sally Field. The film is directed by Marc Webb.