Here's a better look at that Jack in the Box Knuckles Toy Figure.
JIB had one of the first Sonic 3 promoations so they had some-what of a grasp on what Knuckles was supposed to look like, but not quite 100%, as evidenced by the wierdness going on with the spikes vs. the back of his head, and the somewhat-fat looking body & small feet. They got the large fists right, & the tail too...but sadly his eyes aren't really looking in the same direction giving the figure a bit of a strange impression.
Because Jack in Box restaurants were not nation-wide in the USA, this figure is not that common.