Once again the party has been discovered mid-heist and is running from the local guards through the city streets, trying to evade capture. They round a corner, momentarily disappearing from view, “Honey-bells stops once around the corner, turns back and casts Minor Illusion, creating an image of a row of sharpened stakes stretching across the width of the alley.”
Can Honey-bells do this?
The Illusion school cantrip Minor Illusion reads in relevant part:
You create a sound or an image of an object within range that lasts for the duration. The illusion also ends if you dismiss it as an action or cast this spell again.
If you create an image of an object–such as a chair, muddy footprints, or a small chest–it must be no larger than a 5-foot cube. The image can’t create sound, light, smell, or any other sensory effect. Physical interaction with the image reveals it to be an illusion, because things can pass through it.
The question here is if this row of stakes is an object.
Let’s start with Chapter 15 of the Basic Rules for some guidance on what an object is in D&D:
For the purpose of these rules, an object is a discrete, inanimate item like a window, door, sword, book, table, chair, or stone, not a building or a vehicle that is composed of many other objects.
This text is going to turn out to not be very helpful. The word “discrete” tells us that it is a single thing, so it seems like the wall of stakes doesn’t work since it would be many objects. It might also seem that the “not…composed of many other objects” language backs this up. However, the text is slightly ambiguous on that last part, whether it’s just buildings or vehicles which count as being composed of many other objects, or if the earlier “like a…” in the text extends down to the larger items, “not like a building or a vehicle that is composed of many other objects.”
That’s all going to sound terribly pedantic, but here’s the rub: a window isn’t a single discrete object. It’s a wooden frame, one or more panels of glass, and probably a few other bits holding the thing together, and maybe a latch or something to keep it closed. A door could be made from multiple planks of wood, it can have a knob, and what about the hinges, or at least the halves of the hinges attached to the door? A sword has one piece of metal for the blade and hilt, but the cross-guard is a separate piece, as is the pommel, and there may be a leather grip added. A book is made from many pieces of paper (often 1 physical piece for ever 4 pages), a separate cover, and thread or some sort of glue holding it together. Tables and chairs are made from multiple pieces of wood, have nails holding them together, and a chair may have some sort of fabric or cushion added.
A stone though, a stone is a single discrete object. We’re not going to get into molecules and atoms and all that. Lawyering is in the humanities field, not science.
By any definition of an object though, a row of stakes would seem to be a row of several objects, and not a single discrete object.
What about a caltrop? Not a bag of caltrops, but just a single caltrop. Seems like a stupid question, of course a single caltrop is an object for purposes of Minor Illusion. Why am I even asking a question with such an obvious answer?
“Honey-bells stops once around the corner, turns back and casts Minor Illusion, creating an image of a five foot wide cheval de frise.”
And just in case the DM is about to rule that this is actually something composed of multiple objects, Honey-bells’s player quickly adds, “Except that it’s made from a single piece of metal.” How one would engineer such a thing doesn’t matter because this is a magical illusion.
Now we arrive at the conundrum Minor Illusion has created: there are some things you cannot produce as an illusion because they are multiple objects, but you can produce a similar effect with a more complicated object. If a stone is an object, a pile of stones would not be. But, a seeming pile of stones, where the stones have stalks going into the middle of the pile all connecting them together, like a giant stone head of broccoli… that’s just one object.
It just doesn’t make sense to have a cantrip-level spell where there’s a loophole through increasing the complexity of the illusion.
So what do you do as a DM?
You go back and reread the rules on objects, paying close attention to the introductory clause: “For the purpose of these rules…” The rules in reference in that chapter are specifically how to handle players attacking or otherwise damaging objects. It gives them an AC, and hit points, and damage immunities. It’s not a general definition meant to apply across the entirety of the game, putting us back at square one.
Here’s what I’d recommend: Think of “an object” as being something unified not physically, but conceptually. A row of spikes has multiple physical objects, but it’s a single unified concept. Same would be true of not just a caltrop, but a 5×5 field of caltrops. A treasure chest is a single idea, and so is a treasure chest filled with gold coins. This doesn’t seem to let Minor Illusion get abusive, and avoids silly workarounds like “it’s not a chest filled with gold coins, but rather a wood carving of a chest filled with gold coins, painted realistically.”