Imagine a large piece of technology made by trancendents, with the dimensions of a ship cryptosleep casket, that, when activated, can do nearly anything, but will probably only arrive to your colony once per play through. Think about it, it could save a dying colony or bring an entire city to its knees.
The utility of these would be changing up the story of the game since Rimworld is built around stories. This could be small, like providing some convenient resources for a building project, or something such as saving or destroying a colony. But it doesn't end there, it can, and often will, do the absolutely bizarre. You need an extra colonist? It might "eat" a nearby pet and turn it into a person. You want to try to sell the box to a merchant ship? It might shoot it down, thus giving you most of its loot but ruining relations with all of the factions. If you damage it, it might explode and burn the colony to the ground. Or it might "eat" a nearby colonist and perform any sort of operation on him/her from healing brain injury to chopping off all limbs.
I also imagine that different factions will have different reactions to seeing this box in your colony. A raid could flee, be driven into a rage that doesn't follow them to flee, or become friendly to you. If you try to sell it to a merchant, it will probably activate and they (the merchants) might react in any of the above ways. Of course, this is only a secondary thing to the main idea above.
it's not a transcendant box, its chaos not control box loool ^^