The Gelatinous Cube is a dangerous object featured in the 2020Disney/Pixar animated feature film, Onward. It is a volatile object that disintegrates any other object it absorbs in its path.
The gelatinous cube is a large, green chunk of gelatin as its name suggests. According to Barley Lightfoot, it is one of the gauntlet's deadliest traps at Raven's Point. Those caught inside a gelatinous cube will have no chance of surviving the gauntlet.
Role in the film
On their way to find the Phoenix Gem at Raven's Point, Ian, Barley, and their father enter a dark chamber of 1,000-year-old dead knights to which upon arriving, the three encounter an enormous gelatinous cube chasing them across the way. During the chase, the cube absorbs Wilden's coat, cap, and shades, which suddenly disintegrates, just as the elf brothers avoid it and use it as a bridge to continue their way to find the Phoenix Gem.