Here's a 'deluxe type' dog-tag necklace that was a SegaWorld Sydney exclusive item. A usual 'dog tag' is just a flat metal oval shape with whatever words/designs pressed in. This one is deluxe because it uses 3 colors of enamel in the pressed in design for SA1 style Sonic & his name. Also, because it has an added black rubber bumper around all the edges & hole to make it more comfortable to wear / take away the harsh edges.
It is on a standard/normal beaded metal chain (as is expected of such tag necklaces) Because SW Sydney closed not long after, this is a later item for them, but with 'wierd walkin' Sonic' it's a very early SA1 piece. (As that stock art fell into disuse because it was a bit odd) This was bought around 2000.