Can I use Disguise Self to make myself so thin that I can't be seen?

Question

I've asked this question on the DND Beyond forums but I wanted opinions from more people since I really don't see how this would not be possible unless your DM outright said no to you doing it.

The description of 𝘋𝘪𝘴𝘨𝘶𝘪𝘴𝘦 𝘚𝘦𝘭𝘧 states:

You make yourself, including your clothing, armor, weapons, and other belongings on your person, look different until the spell ends or until you use your action to dismiss it. You can seem 1 foot shorter or taller and can appear thin, fat, or in between. You can't change your body type, so you must adopt a form that has the same basic arrangement of limbs. Otherwise, the extent of the illusion is up to you.

The changes wrought by this spell fail to hold up to physical inspection. For example, if you use this spell to add a hat to your outfit, objects pass through the hat, and anyone who touches it would feel nothing or would feel your head and hair. If you use this spell to appear thinner than you are, the hand of someone who reaches out to touch you would bump into you while it was seemingly still in midair."

My question is that, hypothetically with 𝘋𝘪𝘴𝘨𝘶𝘪𝘴𝘦 𝘚𝘦𝘭𝘧, as long as you do not alter your body type or arrangement of limbs (giving yourself extra limbs or anything that your character wouldn't have as a body part), you could give yourself some form of pseudo-invisibility by making the illusion of yourself almost infinitely thinner than you actually are so that you couldn't be seen with the naked eye unless the enemy or anyone around you had a special sense like truesight or blindsight, therefore giving you the bonuses of invisibility without actually being invisible. This is unless someone bumps into you, which the spell says you keep your actual body proportions, so even if you appear thinner, if someone were to bump into you they'd bump into what appeared to be thin air, but was actually you.

An example would be:

You're hidden in a tree on a battlefield with a sniper rifle, musket, bow, etc. You make your attack, and now the enemies have heard/seen where the bullet/arrow/spell/etc. has come from. They approach your tree and then look up, seeing you sitting on one of the limbs. of course you aren't hidden anymore.

Now, say you do the same thing but with your "invisibility"; the enemies rush to the tree where they heard the shot ring out from and look up and alas, no one is there. They could use a perception check to try and find you in the tree or maybe they could fire blindly into the tree, rolling with disadvantage, but as long as they didn't pass the perception check or hit you, you would still be "invisible" and they still would not know your exact location, meaning if you really really wanted to you could also just move to a different location and repeat the same process while maintaining your endless advantage over enemies.

Lastly, this is where I started to get confused when people told me you physically couldn't do this; 𝘋𝘪𝘴𝘨𝘶𝘪𝘴𝘦 𝘚𝘦𝘭𝘧 itself says this: "...You can't change your body type, so you must adopt a form that has the same basic arrangement of limbs. Otherwise, the extent of the illusion is up to you." which IMO debunks the whole argument of "You can't do that, it doesn't say that." because in the description of the spell it once again states that as long as you do NOT change your body type or your arrangement of limbs the extent of the illusion is up to YOU, the player, meaning you should definitely be able to do it as saying this means the player can make the illusion go to insane extremes like in my example, as long as the DM rules it.

Answer 1

I really don't see how this would be possible unless your DM outright said yes to you doing it. And they shouldn't.

Spells only do what they say they do. The description does not say you can appear infinitely thin. It says "you can appear thin, fat or in between". Reading this with a modicum of common sense, it is clear this is to allow a plump halfling to appear as a slender gnome, for example.

Even if it did, nowhere in the rules is there an "appearing infinitely thin" condition. Nothing prevents the enemies from seeing you.

So it comes down to a DM ruling. I've seen discussions about using it as camouflage for Advantage on hide checks. That's one thing.

In this case the simple fact is that a level 1 spell should not be able to eclipse a level 4 spell (Greater Invisibility except this has a longer duration and doesn't require concentrating).

Answer 2

Disguise Self cannot be used to appear invisible

This has been covered in the closely related questions Does disguise self make parts of you invisible? and Disguise self to 0 height.

Disguise self to infinitesimal thickness is just another variation, and does not work for the same reasons: the spell does not say it makes you invisible as per the game mechanics, so it does not.

That is apart from power level considerations that if it could, that would let disguise self, a concentration free level one spell do what otherwise would require concentration and a level two (or even four, because it does not drop if you attack) spell. It is obvious that that cannot be how it works.

Answer 3

I would outright say no to you, but I shouldn't have to.

First, in general, spells do what they say and nothing more. This rule has, in the past, led to some silly interpretations, but I think it is spot-on here because this question deals with already defined game mechanics. "Invisible" is a condition in 5e, and nothing in the text of the spell states or implies that invisibility is conferred by the spell.

Second, in general, a lower level should not be assumed to be able to replace a higher level spell. Disguise Self is a first level spell; Invisibility is a second level spell.

Third, as mentioned elsewhere, when in doubt, default to plain English and common sense. It's purpose is to disguise and appear different, not to hide and appear not at all.

Answer 4

No, simply because ....

keeping your body type also means to keep a third dimension. Or, in other words: No (living) gnome ever has been indefinitely thin.