Wow! Here are some real deal real cool prototypes to see! AND they're packaged for extra rarity!
These are the prototype figures by ReSaurus for E-102 Gamma, Big the Cat & Amy Rose, each on their card and with their accessories. Each one is made of red proto plastic (it's kind of typical to cast figures like this in some random color to see how the sculpt and action will work/look, before setting them up in their final color, then painting it) The ring is set in gray plastic (as you know this was electroplated to gold later) & everybody has their relief base. Amy's got her mallet & Big has his fishing pole. The hip plate is missing on E-102, but that's seemingly the only part that's not there. The box backs are completely blank/featureless & of course, all the printed inserts like the logo & portrait aren't in yet. The ring stands (these were clear) may also not be in. (Interestingly, the Amy looks a little better unpainted than she did with paint)
Just what were these for?
It's the 2nd set of figures from ReSaurus, so they probably weren't trying to prove something (or maybe they were? Their Sonic wasn't that great) so possibly for a toy show, or just some kind of package test or a proof. No matter what though, they're super interesting to look at. Maybe they are one of a kind, too.

The ReSaurus prototype Big & Gamma turn up again, this time in 2019, and for over $1,000 each on Ebay. Now, some new angles are provided, like the back of Big & the top of E102. The top shows he's packed with that removable levitation-helper flat/device already mounted to the figure. The back of the box-mockup is (as thought) just a simple white cardboard card with staples holding on the bubble.
Notice that the bubbles are turning yellow with age. Some clear plastic does this, and there is likely no cure.