Tesseract

The Tesseract, also known as the Cube, is a crystalline cube-shaped containment vessel for the Space Stone, one of the six Infinity Stones that predate the multiverse and possesses unlimited energy.

The cube was later obtained by Supreme Leader Victor Nevarez in order to enable its use as a power source to complete the giant space battleship Lord Trethium's Wrath.

Capabilities
"The fatherland is calling its children! This cube that I'm holding will complete the largest and most powerful spaceship of all times!! THE PRIDE OF THE COALITION WILL RISE!!!"

* raising their fists upwards* "SIEG HEIL!!!"

--Victor Nevarez and the Chaos Council

The Tesseract is one of the most powerful artifacts in the multiverse. According to Nick Fury, it holds great power that is almost unlimited; Black Widow tells Bruce Banner it has the power to wipe out a planet.

The Tesseract can open rifts through space. This is how Loki transported himself and later, the Chitauri, to Earth through portals. Thor and a muzzled Loki use the Tesseract to teleport back to Asgard. In an altered timeline, Loki used this to escape following the Battle of New York after the Tesseract landed at his feet due to a mishap with the Hulk.

It can be used to power other weapons. Tesseract-powered rifles held by Dark Thunder Guards were particularly devastating, as a single shot could completely disintegrate an opponent.

Besides its use as a weapon, the device can harness and channel a seemingly unimaginable amount of field quanta to protect itself from being attacked by other energy sources, as seen when the field region, surrounding the tesseract, proved to be completely impervious to Iron Man's repulsor beams. This prompted Jarvis to state that the cube's barrier is "pure energy", confirmed in one way or another by Loki and Thor on later occasion.

The Tesseract can also show visions of the future, which may or may not come true. The people who have seen this power are the Red Skull, Eric Selvig, and Hawkeye, when the latter two were under the control of the Chitauri scepter.

It cannot be held by mortal hands. Anyone who does so will be disintegrated, their remains sent to another world, as evidenced with what happened to Red Skull. Fury very briefly touched it to move it with gloved hands, and had to drop it very quickly. When Red Skull touched it, he was apparently disintegrated and sucked through a wormhole towards Yggdrasil. Though he was believed dead, Red Skull was instead transported to Vormir where he was to cursed to become the keeper of the Soul Stone.

The Tesseract houses one of six Infinity Stones, the Space Stone.