From the minute they started this movie I knew it would be a let down...I'm old school comic book and there was no good way to introduce the black costume this quickly.
For those not in the "know", here's a quick comic run down:
Spidey was on a alien planet fighting in the
secret wars.
His costume was tattered so the aliens showed him a machine that plopped a black goo ball out of it. Spidey grabs it and it oozes over him. Intro of the black costume.
What spidey didn't know was that the goo was a alien symbiote that when connected to spidey was forming a "relalationship" of sorts. It's emotions were plauging spidey causing him to become dark.
So, the Fantastic 4 analyze it, figure out that the costume is alive and blast it from his body with a vibro gun. It somehow escapes and then gets back with spidey finally ending up in the bell tower where Eddie Brock was. It joins with him, intro Venom.
http://en.wikipedia.org/wiki/Symbiote_(comics)
I know, major geekness, but that's how I rolled in Middle and some of High School. ;0
I'm going to see it with my kids this weekend, we'll see.
Steve