The alien in “Super 8” needs cube-shaped objects to repair its ship. The film presents these white cubes as pieces of a strange, shape-shifting material that can assemble into a spacecraft.
In J.J. Abrams’s 2011 science-fiction thriller, a group of children filming a movie witnesses a catastrophic train crash in 1979. The crash releases an alien and scatters cargo containing the mysterious cubes. The alien then searches for the scattered material, because the cubes are components of the vessel that brought it to Earth.
The cubes are more than ordinary mechanical spare parts. They can move, combine, and reconfigure under the alien’s influence, giving the final ship-rebuilding sequence its distinctive visual effect. The movie gradually reframes the creature: although it attacks people while frightened and trying to escape, its central goal is to leave Earth and return home.
A common mix-up is remembering the cubes as the ship itself. That is close, but the story shows the spacecraft disintegrating into cubes and later reconstituting. “Cube” is therefore the canonical shape-based answer, even though the film treats the objects as advanced, shape-changing material.