It's very funny to me that the stereotypical gelatinous cube is bright fucking green when the monster itself is almost perfectly transparent. Like its gimmick is that it's a monster that imitates an empty 10x10 hallway. How many people have fallen victim to gelatinous cubes because they "know" that the ooze is bright green and so don't bother to check the suspiciously clean corridor in front of them.
The cube is green because oh my god do you know how hard it is to draw a perfectly transparent cube? Especially in isolation, like in the monster manual? Even if you put debris in, it reads as "floating skull ft. helium sword." Awful. Absolutely wretched.
I'm picturing it appearing in in-universe bestiaries with a little caption like *specimen dyed for visibility.
Dungeon naturalists sneaking up on a cube with a bucket of green dye so they can see it well enough to study it.
