Tesseract

Part 1: The Dossier: An At-a-Glance Summary

1)
This distinction is crucial; the cube itself is just the vessel, while the blue gem within is the true source of power. However, the two are almost always referred to collectively as the Tesseract.
2)
The name “Tesseract” is a mathematical term for a four-dimensional analogue of a cube, which fits its mysterious, otherworldly nature in the MCU.
3)
In the comics, the Cosmic Cube's power is often described as being second only to artifacts like the Heart of the Universe or the Infinity Gauntlet itself when fully assembled.
4)
The Tesseract's glowing blue prop in the MCU was a deliberate visual choice to match the blue color of the Space Gem from the comics, helping to foreshadow the eventual Infinity Stone reveal for observant fans.
5)
Source material for the original Cosmic Cube saga can be found in Tales of Suspense #79–81 (1966) by Stan Lee and Jack Kirby.
6)
The Secret Empire storyline, showcasing Kobik's power, was a major 2017 crossover event primarily written by Nick Spencer.
7)
In the Loki series, the TVA is shown to have drawers full of inert Infinity Stones from pruned timelines, including multiple Tesseracts, which are used as paperweights by office workers. This moment served to establish the TVA's immense power by trivializing the MCU's most sought-after objects.
8)
The first time the Tesseract is seen in the MCU is in the post-credits scene of Thor (2011), where Nick Fury shows it to Dr. Erik Selvig, who is unknowingly under Loki's influence.
9)
Despite both being powerful blue cubes often sought by villains, the Tesseract has no connection to the Casket of Ancient Winters, the Frost Giant relic seen in the first Thor film.