Tesseract

For a full history of the Tesseract, see Space Stone.

The Tesseract was a small, cubical, blue vessel that housed the Space Stone in Earth-199999. For much of its existence, the Space Stone's powers were attributed to the Tesseract itself, but in truth it was merely a vessel. Having held the Space Stone since time immemorial, the Tesseract has been at the center of many epic conflicts. Thanos destroyed the Tesseract in 2018 in order to claim the Stone inside as part of the Infinity War. Another Tesseract from an alternate timeline was introduced into the universe's central timeline as part of the Time Heist, but it too was destroyed by the Avengers in order to better use the Space Stone.