Fun ways to use the Gelatinous Cube in your game

This is a monster that behaves more like a living trap: its translucent, its potentially deadly, and involves skill checks to escape. Below are a few examples of the ways you can use gelatinous cube, apart from the other oozes in the Monster Manual.
Players are in a maze occupied by several gelatinous cubes. These cubes follow a predictable path that loops. The PCs can learn the safe routes by following the paths that are dirty or covered in debris. Paths that are spotless are the trails the gelatinous cubes follow, since they digest everything else in their path.
The players stand at the bottom of a steep staircase, unknowingly standing over a trap lid on the floor. When a PC triggers a pressure plate on one of the top stairs, the staircase will fold into a slide and the trap lid will move away to open up to a pit in the floor which contains a gelatinous cube.
A gelatinous cube has a magnet stuck in its body, and PCs that get within 15 ft. of the cube (while holding another magnet-like object) will have to beat a STR DC check or be pulled into the cube.
A gelatinous cube contains a downward-facing sword in the middle of its body. From a distance, the sword appears to be floating as if by magic, though checks to identify magic would fail since there’s nothing there to detect… unless the spell caster picks up the magic of an even smaller magic object instead, like a ring.
Have you used a gelatinous cube in your game? Reblog this post with your story!