Very interesting, Shadow's inhibitor rings were part of the original concept from the very beginning. They weren't created for Sonic X, the anime was simply the first to showcase them.
The concept itself was created by Kazuyuki Hoshino.
It's so hilarious that between Toy Story 2 and 3, Woody and Buzz meet a group of toys claiming to be regular people from another dimension, then they meet a god who torments them and turns Buzz' weapons real, and they're all like "ah ok" and never mention it again.