Bee mask!
Oh god, that thing is so amazing! D: I happened to stumble across with those helmets in Prisma (a local supermarket) and was immediately struck by a strong urge to just finger with one. It was so cool. There were three buttons on the side of Bumblebee's head, and if you pressed the buttons the helmet made sounds familiar from the movie. Even the amazing transformation sound, I love that sound. Too bad I couldn't try and fit it on, though it most likely wouldn't have fitted anyway. It's designed for small children after all.
I'd buy it, if it was a couple ten euros cheaper. After all, how cool would it be to have a Transformer head in your shelf on display? (Cool, and kind of cruel, too)