Here's another (well deserved) look at the uncommon Swatch Watch with Sonic Adventure theme. The watch itself, and it's trasparent plastic 'box/tube' thing already appear on Gear accessories, but what didn't appear is the special feature!
The watch face has a normally (from straight on) invisible hologram effect in it! When turning the face / tilting it in the light a Sonic face appears in shimmering hologram color. This is hard to photograph, but they've sort of caught it in 3 phases there at the bottom.
Why wasn't this known before? The package didn't describe it as a feature, the watch itself is uncommon, it started off expensive so nobody much got it, and you probably have to debox it to really access/notice the feature.
Still, this is cool to know about and to see. It makes the watch even more desirable as a collectible.