You'll probably have a better chance if you post more details like the booth number where it can be found, *exactly* what it's called, and a picture of the actual item. SDCC isn't the kind of place you can just "pick up" something. It's crowded beyond imagining, and just massive. It's incredibly easy to miss an entire booth(and not just the small ones) due to the crush of people. Even if you know what you're looking for and where to find it, it can be really hard to get a specific item.
That's why I stopped hunting for other people. Tracking down even one or two items could take hours in that crowd, and my husband would get frustrated so we'd spend the con fighting. And then there's the hours of dragging somebody else's dead weight around the con to deal with once you find it. I've offered to pick up a few things for a friend, and usually spend the entire day doing it. I looked at things for myself in between my friend's booth stops, but that was pretty much my whole day. Now my husband gets really upset if I offer to go hunting at SDCC because of a lot of bad times. I don't blame him:/ I hunted for friends for years. I started calling it "divorce con" because if all the fights from trying to navigate all those toy lines.
I was there today, and since what you're looking for is small and light(and cheap), I kept an eye out for Skylander anything to see if I got lucky. Besides some guy dressed as one just wandering around, I didn't see anything even remotely like that. I could have been standing right next to it, but if it was near one of the many bottlenecks or lines, or they were giving away freebies at a booth nearby, I never would have seen it. I did look, and I covered the whole floor, but it was chaos today.
I'm heading home tomorrow(just in for the day), but maybe somebody else can help you. If you post the information I suggest, you'll make it 100X easier for someone to find it, and make it that much more likely you'll get your item. I'm sorry I couldn't find it today. Good luck!