I noticed that when I first saw this trailer on July 22nd, but I just thought it was a black spot,nothing to worry about.
This could be the way the scene goes down...
Eddie is walking into the church, sits down, and begins to pray to God. "It's Brock, sir." Meanwhile, Parker lands in the elltower above, and begins to scream as the bell puts him in extreme pain. "I'm here humbled and humiliated." Parker then realizes that loud sounds weaken the evil black symbiote, and begins to painfully and slowly rip off the suit he is in. "..to ask you for one thing." (loud scream we hear in the last part of this trailer from Peter) "I want you to kill Peter-" (Brock hears the scream this time and looks up, saying his line from the teaser) "-Parker!" Brock begins to cry, realizing now that Parker all along was Spider-Man, and as Parker swings out of the belltower in nothing but underwear, the symbiote hears Brock's cry. Slowly, the black material drips down, and as Brock looks up, it engulfs him. A painful sound emerges from Eddie, and he screams in the loudest voice possible. We see the black suit begin to cover Eddie's body which is now growing tremendously into a giant monster, and Eddie's high pitched scream turns into a very deep, dark roar, as he looks up to the camera. He has become Venom.
^^^That would be AWESOME!!!