My parents bought me a pineapple plant a short while ago. After the pineapple finished its cycle a new plant sprouted. Due to its quick growth we thought it was a weed but it kind of looks like a tree and it has these weird spiky balls that grew after the purple flowers fell off. I don't know much about plants so I'm attaching a picture in the hopes that someone can tell me what it is... it's hard to see because I used a web cam but the circular shapes are incredibly spiky.
I was thinking Datura stramonium as well. They grow fairly rapidly but as I recall, and this would need to be checked, the seeds don't grow really fast to maturity. It takes awhile for them to produce flowers. So my guesstimate would be the plant was dormant in your pot. As opposed to Brugmansia (the Angel Trumpet) this one is often called the Devil's Trumpet. That is supposedly because the Angel Trumpet flowers point downward (as in from Heaven) while the flowers of this one point upwards (as in, well, you get the idea).
