@aescling @wallhackio not quite related, but I love the breakdown on Sonic Retro of the Chaos Emeralds. https://info.sonicretro.org/Sonic_the_Hedgehog_(2006_game)#Emerald_Accounting

The short version: The Blue Emerald exists in a timeloop during the entirety of the game, so how does it exist outside of the game:

The long version:

This is the Emerald which finds itself locked in an ontological loop over the course of the game. The blue gem is implied to have been Princess Elise's lucky charm for many years, and Dr. Eggman attacks the Festival of the Sun to steal it from her. Elise throws the jewel to Sonic as she is being kidnapped, and Sonic takes it to White Acropolis as a ransom, where it goes in Eggman's time machine. Silver later takes the blue Emerald from White Acropolis after beating the Egg Genesis, and uses it (with Shadow's assistance) to open a portal to the past and the Solaris Project. Silver then gives it to a 7-year-old-Elise, who presumably keeps it with her for the intervening 10 years until the Festival of the Sun is attacked. The problem here is that the blue Emerald never enters or leaves the loop; it didn't exist chronologically before Silver brings it to the Solaris Project, and it doesn't exist after Silver and Shadow warp out of the Radical Train fight arena. And, since it's been with Elise for the 10 years before the game, how did Sonic and Shadow use it to turn super and defeat Perfect Chaos, Finalhazard, Metal Overlord, and Devil Doom?