- Erik Selvig: "What is it?"
- Nick Fury: "Power, doctor. If we can figure out how to tap it, maybe unlimited power."
- ―Selvig and Fury about the Tesseract.[src]
The Tesseract is a cubical object, possessing immense power. It is a nearly unlimited supply of energy, and this energy can be used to open a portal between any two realms in the universe. It appears to be indestructible.
World War IIEdit
Most likely originating from the realm of Asgard,it was left behind on Earth by Odin after he defeated the Frost Giants. In 1942 the Tesseract was preserved in a church in Tønsberg, Norway on Earth, until the church was destroyed by Johann Schmidt, the leader of HYDRA, who stole the Tesseract and took it back to their headquarters to be experimented on by doctor Arnim Zola.
After experiments made on the Tesseract, Schmidt and Zola were able to use the object's power to create highly advanced weaponry, fueling Schmidt's plans for world domination. Schmidt later installed the Tesseract into the Valkyrie with which he planned to destroy some of the world's largest cities, until his plan was thwarted by Captain America, who accidentally activated the Tesseract. Schmidt, angered at Captain America, quickly took the Tesseract and a portal to another realm temporarily opened, pulling Schmidt in as it closed. The Tesseract fell and burned through the floors, causing it to plunge into the sea below. Some time later, it was recovered by Howard Stark - CEO of Stark Industries and a founding member of S.H.I.E.L.D. - who was looking for his friend Captain America.
By 2009, the Tesseract had been in S.H.I.E.L.D.'s possession for some time and the World Security Council ordered S.H.I.E.L.D. to make one of its primary objectives to reignite the Tesseract, a project titled Project P.E.G.A.S.U.S. Nick Fury, director of S.H.I.E.L.D. instead turned his attention to the recovery and surveillance of extraordinary people for a program that would later be called the Avenger Initiative.
A year later, Nick Fury hired Erik Selvig, a scientist, to do experiments on the Tesseract in a base in the Mojave Desert. Fury also positioned Hawkeye in the base to protect Selvig and the Tesseract. After some time, Fury was called to the base by Selvig due to strange activity emulating from the Tesseract, and soon Loki - who had been using Selvig as a conduit to look at Earth - was transported to the base by the Tesseract, who killed several S.H.I.E.L.D. agents and enchanted Selvig, Hawkeye and a number of other agents into following him, while taking the Tesseract with him to an undisclosed location.
In response, S.H.I.E.L.D. decided to start the Avengers initiative, and swayed Bruce Banner, Iron Man, Captain America and Thor to their cause. After some time, Selvig installed the Tesseract in a shielded device on top of the Stark Tower in New York City, where it opened a portal to the Chitauri homeworld and an army of Chitauri under Loki's command were unleashed into the city. The Avengers fought off the alien attackers, while Black Widow reached the Tesseract and found Selvig coming back to his senses. The two of them disabled the Tesseract and closed the portal, and the Tesseract was later taken back to Asgard alongside Loki by Thor.
It was used by Heimdall to repair the Bifrost Bridge and then sealed inside Odin's Vault. Loki later took the Tesseract when Asgard was about to be destroyed, which proved to be a fatal mistake, as Thanos sensed that the Stone is with Loki and attacked the ship used to evacuate the Asgardians and succesfully retrieved it and massacred half of the Asgardians.
- The Tesseract is based on the Cosmic Cube seen in the comics.