Can creatures with Air-form/Water-form/Fire-form/Amorphous squeeze into spaces smaller than 1 inch?

Question

There are creatures in DND 5e with abilities that allow them to move into spaces as small as 1-inch without squeezing: Air-Form from Air Elementals, Water-Form from Water Elementals, Fire-Form from Fire Elementals, and Amorphous from Oozes.

Therefore can these creatures move through spaces smaller than 1-inch if they use the rules for squeezing? If so what's the smallest sized space that they'd be able to squeeze through in your option?

For reference the rules for squeezing are:

Squeezing into a Smaller Space

A creature can squeeze through a space that is large enough for a creature one size smaller than it. Thus, a Large creature can squeeze through a passage that's only 5 feet wide. While squeezing through a space, a creature must spend 1 extra foot for every foot it moves there, and it has disadvantage on attack rolls and Dexterity saving throws. Attack rolls against the creature have advantage while it's in the smaller space.

Answer 1

That would be a good house rule, but it's not an official rule

The rule you cite says only:

A creature can squeeze through a space that is large enough for a creature one size smaller than it.

A Large air elemental can use this rule to squeeze into a five-foot space, but this rule doesn't give it the ability to squeeze into smaller places.

We at rpg.stackexchange don't have the authority to issue house rules for you, not even if it really seems like it would make sense. Only your DM can issue house rules for you.

The only question we can answer for you is whether something is an official rule.

And this isn't one.

Answer 2

No, the amorphous trait doesn't interact with the Squeezing rule.

Rules only do what they actually say, and you're reading something into the rule that isn't there.

"Squeezing into a Smaller Space" says

A creature can squeeze through a space that is large enough for a creature one size smaller than it.

It doesn't say "you can squeeze to fit through a hole half the size you'd normally need". It only talks about creature sizes. A medium creature with Amorphous is still medium sized, so the squeezing rule only applies to spaces that a Small creature can pass through without squeezing (in which case Amorphous lets you do the same thing without taking the penalties for using Squeezing, so you can pretty much just ignore squeezing entirely).

Whatever size your character is, if you see a 1-inch hole, amorphous says you can use that opening. If you see a 3/4-inch hole, it's too small for amorphous. Squeezing doesn't care about that, it only says "Is it big enough for a creature one size smaller than you?"

I think the easiest way to think of this is a little like having two armor class calculations available. You can only use one of them at a time, so when it comes up, you pick whichever one is more useful in that particular circumstance. If you decide to use Amorphous, then you aren't squeezing. If you decide to squeeze, then you aren't using Amorphous.

Now, you could get into an odd situation with this. It's certainly possible that you could be playing a halfling or kobold who has gained the Amorphous trait and then casts Reduce to become Tiny, or you could have a Rat familiar that has somehow become amorphous (gross), at which point there actually isn't a size category smaller than Tiny for the squeezing rules to reference. In this case, for an opening of an inch or larger, you don't need to worry about it because amorphous clearly works, but for smaller openings, it's largely up to the DM to decide whether the creature can squeeze through. However, if the DM decides they can get through it by squeezing, Amorphous is irrelevant to that; a non-amorphous rat familiar or Reduced kobold could get through it anyway.

Of course, your DM might decide differently and allow you to use Amorphous AND squeeze at the same time to get through even smaller openings. But by the rules as written, for most player-character purposes, an amorphous (or similar) creature never needs to squeeze, because they have another ability that's superior in every way.

Answer 3

They can squeeze into smaller spaces than 1-inch

The rules for squeezing state that "a creature can squeeze through a space that is large enough for a creature one size smaller than it" (emphasis added).

Since Air Elementals, Water Elementals, Fire Elementals, and Oozes are all creatures; they qualify for using the squeezing rules.

Now you might say in response that if the Ooze and/or the Elementals aren't at least small sized creatures, than they can't possibly use the squeezing rules to squeeze into a space that is smaller than 1 inch because the squeezing rules only allows a creature to "squeeze through a space that is large enough for a creature one size smaller than it" (emphasis added); therefore only small Oozes and elementals can squeeze through spaces that are smaller than 1 inch because (spaces smaller than 1 inch) are only accessible to tiny sized creatures and the only sized creatures that are one size bigger than tiny are small.

To this I refer you to Can Medium creatures squeeze into smaller spaces?'s%20only%205%20feet%20wide.

The accepted answer to this question is that "Space does not only mean the area that you control in combat" (emphasis added); this means that although an Elemental or Ooze may command a space of a creature of size medium/larger for combat purposes, it does not translate to them physically occupying a space of that size.

If all that didn't convince you I'll refer you to whats stated in the description of the abilities that Oozes, Water Elementals, Fire Elementals, and Air Elementals have: can move into spaces as small as 1-inch without squeezing (emphasis added).

The fact that the abilities of these creatures state that moving into spaces as small as 1-inch can be done without squeezing, implies that these creatures can move through even smaller spaces if they decide to squeeze (emphasis added).

As for the smallest spaces I'd allow them to squeeze through I'd say a 1/2 inch space. DND 5e has no rules we can use to determines this that I'm aware of, so the answer to this part of your question is completely up to your DM.