Wow, that's interesting. I've yet to see a bootleg one myself.
As for negging the seller, have you explained the situation and asked for a refund? Not siding with the seller or anything, its just that maybe they didn't even know it was bootleg themselves. I looked at that seller's other items and it doesn't look like Bakugan is their specialty. They could have been scammed by the persons that they originally bought the bootlegs from without knowing it. Just a thought... as a seller myself I tend to look at things from both angles.
IMHO, I'd request a refund from the seller (if you don't want the bootleg... lol) and see what happens. If they don't want to refund your money then I would think a negative feedback is in order. I'd also think about reporting them to Ebay for selling counterfeit items... even if they didn't mean to do so. That is to protect any other buyers out there that might not know any better, not to punish the seller. Based on what I saw in their listings, I'd say selling the bootlegs was probably an honest mistake... ie they didn't know any better. You never know though.
Thanks for taking the time to post the video... I'll have my eyes peeled next time I'm at the Flea Market... lol.