What options exist for making non-equipment objects invisible?

Question

I'm the DM of a 5th-level party whose PCs have a handful of illusion spells in their repertoire. The players have on at least one occasion mentioned the idea of using one of these spells to hide some important object -- not by covering it with the image of another solid object, but with an illusion of open air. The question "Can you create an illusion of empty space?" already covers that scenario, where the accepted answer strongly implies it shouldn't work. But what about spells that are expressly designed to make objects invisible?

Invisibility (and Greater Invisibility) works on creatures and their equipment, but the types of objects the players want to hide are things that can't exactly be carried on someone's person (e.g. a cart, a statue, a mound of dirt from digging a deep hole). The only spell in the Player's Handbook I found that describes making an object invisible is Sequester, but it's overkill for this situation (7th-level spell, 5k gp in material components, also blocks divination, lasts until dispelled).

Are there any other effects (spells, items, or otherwise) that can make an object or volume invisible? I'll accept any official or playtest publication as a valid resource. I don't necessarily need it to be available/affordable to 5th-level PCs, but I'd prefer something near the level/value of Invisibility, since I'm looking for similar utility.

Answer 1

There is no spell for turning objects invisible at the level you want

As mentioned by you, illusions shouldn't really work super well for this purpose and obviously none of the dedicated invisibility spells target objects (only creatures).

A solution I created for my party: allowing invisibility to target objects

So in a party I DMed for, this exact issue actually did come up when the party wanted to turn a part of a trap invisible. At first, I allowed them to use a modification of invisibility where they could turn an "equipped" item invisible (such as a cloak) and then use that to cover whatever object they wanted concealed.

However, this got to be unwieldy and slow and the rules ("Is your cloak big enough to cover that?" "How big is my cloak?" "Does a tarp count as equipment?"). The rules (or lack of options within the rules) were causing friction and less fun than could have been had.

So, I ended up allowing invisibility to target objects directly. Essentially using the exact spell as written, but allowing it to apply to objects as well. The caster could only apply it to an object or use the normal effect but not both.

It was a more major change to the rules, but it more directly addressed the issue at the table and with the least friction. It helped immensely. The party used it for many clever but not game-breaking things and much fun was had.

If you are the DM, and you see this as being a continuing problem worthy of addressing in a house-rule way, then this is the solution worth considering.

Mechanics and balance

I never ran into any issue when playing with this rule. In fact, I almost wondered why in the world it wasn't a default option. It is worth noting that my players are very crafty but they usually don't try to break things (especially when I am going out of my way to accommodate them).

I do see some potential areas that would need DM judgement. For example, the definition of "object" is intentionally vague in 5e. Thus it will be continuously up to the DM to determine what is considered too big, too complicated, or too whatever-else to be considered an object. Vanish this statue? Sure. Vanish this mountain? Absolutely not. Vanish this cart? Probably.

If you are comfortable with opening yourself up to that, then I honestly see no other downsides. The spell as I modified would only work on an object (as modified) or a person (as originally written) but not both. It is still concentration and costs a valuable spell slot.

I don't think this will work at every table necessarily, but if you think it might solve more issues than it creates at yours, give it a shot.

Answer 2

The rules state that the target is a creature or a person (emphasis mine):

Invisibility - A creature you touch becomes invisible until the spell ends.

Greater Invisibility - You or a creature you touch becomes invisible until the spell ends.

This pretty much specifies that the target has to be some form of living being. That said, Jeremy Crawford covered "targeting" in 5e during a talk. Two particular points he raised on the subject sort of allow an "interpretation" to happen within the rules (emphasis mine):

• If a spell specifies picking a 'humanoid' or an 'object' or a 'creature' it means just that. If you try to violate that, there is a 'little gap in the rules' that 'at some point' they will add in. The 'design intent' is that nothing would happen, meaning the action is wasted, but a spell slot would not be spent. Ultimately, the rules are silent, so it is up to the DM.

Effectively, this would mean that in-universe, the invisibility spell requires some form of "creature", i.e. a beast or human or animal, for it to be turned invisible. This "something" that a creature has, (perhaps a soul??) that inanimate objects, plants, or anything outside of the bounds of the definition of "creature", are obviously missing.

That said, the way that Invisibility works in 5e suggests that the invisibility is somehow "physical". Once again, a tweet from Jeremy Crawford states (emphasis mine):

Only items worn/carried when invisibility is cast are invisible, but I'd let you conceal something under them.

Therefore, a cloak for example, worn by someone that Invisibility has been cast on, can be used to cover the particular item(s) you wish to turn invisible; or even if the PC holds them while the spell is cast, would, by the definition given; turn them invisible for the duration of the spell.

Answer 3

So I think you don't need to change anything. The best spell for this I see IMHO is prestidigitation because it basically it reads as accomplishing any sort of parlor or stage magic trick with magic. Now I think it's important to think of it as magic and not the sleight-of-hand version of these tricks, because it is listed as a spell. Examples would be if you do a card trick, the "is this your card" moment works because you used actual magic to do it (instead of sleight of hand). The main point of the spell is to provide creative roleplaying; its main limit is no mechanical benefit. The benefits of its effects are left up to the DM. So you could snake-charm a rope that slithers into the air and a friend could climb it so long as you keep playing. Have convenient gusts of wind or dark shadows to appear more heroic or scary.

I would rule that since non-magic stage magicians can make all kinds of stuff, including the Statue of Liberty, disappear, prestidigitation could make a trap or cart "appear to disappear". Now it wouldn't be actual invisibility, so I would say someone looking for the cart would have to make a Perception check at disadvantage to notice the trick. But that doesn't mean they know what or why the trick is.

Otherwise, yeah, just invisible target objects of up to Large size (cart but not a house). You could even do a middle ground and say it's still on him or the a living creature, but it affects objects that they are touching when it's cast. Plus 1 creature or object per level or something, so a powerful wizard could hide the whole town as long as they held hands or something. I think the limit of contact adds a lot of roleplaying potential while allowing objects to be invisible.