Tesseract

The Cosmic Cube also known as The Tesseract is a powerful cube that was once own by Odin.

Captain America: The First Avenger
It was guarded by the Asgardians, the jewel of Odin's treasure room of Relics but lost during the last age of worship by men on earth. It is found once more in the in the 40s by Johann Schmidt in a box behind Jormungand in a sculptured mural of yggdrasil world tree. Located inside church full of viking warrior entombed within its walls. Schmidt and scientist Arnim Zola harness the power of the tesseract to be used as weapons against the Allies. Captain America foils Schmidt's plan to use the tesseract to launch an aerial attack on the United States, and Schmidt disintegrates into light that shoots into space when he touches the Cube. After Captain America crashes Schmidt's plane, the Cube is recovered by Howard Stark.

Iron Man 2
While Tony Stark is flipping through his father's notes, a hypercube is briefly seen, possibly alluding to the Cube.

Thor
Years later, the Cube ended in the hands of S.H.I.E.L.D., and Nick Fury, believing it to be just a powerful energy source, asked the aid of Professor Selvig, who unknowningly was under Loki's mind control, to study it.

Powers and Abilities
The Cosmic Cube, better known as the Tesseract, is one of the most powerful artifacts in the universe. According to Fury, it holds great power.

Appearances

 * Canon
 * Iron Man 2 (first appearance)
 * Thor
 * Captain America: The First Avenger