Can an earth elemental drag a tiny creature underground with Earth Glide?

Question

So it's been asked and answered that an earth elemental can't drag anyone through stone as they don't have Earth Glide. That's fine it makes sense.

But, what if the person is tiny and the elemental can envelope them completely while travelling through stone?

And if not does that mean they can't take objects ever?

And the description for the ability says:

• Earth Glide: An earth elemental can glide through stone, dirt, or almost any other sort of earth except metal as easily as a fish swims through water.

This suggests that the elemental parts stone as water and an occupant small enough to be covered by the elemental could travel with them.

Answer 1

Size doesn't matter, Earth Glide applies only to the elemental

Earth elementals do not have the ability to "envelope" a creature to any mechanical effect. They have the exact same normal options as every other creature with regards to interacting with another creature which basically boils down to shove, drag, and grapple.

The fact is, the Earth Glide ability specifies what it can do and to whom and it only affects the elemental regardless of the size of a creature it might be attempting to carry:

Earth Glide. The elemental can burrow through non magical, unworked earth and stone. While doing so, the elemental doesn't disturb the material it moves through.

This interpretation is confirmed as the intended reading by the Sage Advice Compendium as linked in the previous question:

Can an earth elemental grapple with a creature and then pull it underground and leave it there to die?

No. An earth elemental’s Earth Glide is meant to apply to itself only. The elemental doesn’t take other creatures with it when it moves in this way.

There is no mechanical way for a creature to be "small enough to be covered by the [earth] elemental" in the rules such that it would allow it to be affected by Earth Glide because only the elemental can be affected by it at all. There is, in fact, no such thing as being enveloped or covered by another creature anyways outside of specific abilities like Swallow (which earth elementals do not have). And even those abilities do not allow the subsumed creature to be considered merged into the large one such that they are mechanically the same creature.

Simply put, Earth Glide affects only the elemental and no other creature, no matter their size, can be affected by it.

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Your description is not from this edition

You quote a description for Earth Glide in your question:

An earth elemental can glide through stone, dirt, or almost any other sort of earth except metal as easily as a fish swims through water.

However, you should note that that description is not from 5e and thus has no bearing on 5e rulings or rules. It appears to be from 3.5e (thanks @V2blast) which for all intents and purposes is an entirely different game from 5e.

Answer 2

No, an Earth Elemental can't extend its Earth Glide ability to affect any other objects or creatures. (@Rubiksmoose's answer explains why.)

An Earth Elemental might still achieve a similar goal by brute force, for small objects and soft ground.

If an Earth elemental is holding a small object or creature while entering or moving through the ground, they are effectively pushing that object through the earth the normal way. (This would obviously take much more effort and slow them down, so you'd have to decide how much depending on the object and the soil conditions.)

An Earth Elemental is strong enough to drag/push a tiny metal ball bearing (for example) through loose earth or soil, boring a tunnel as the ball pushes earth out of the way. The object doesn't glide, but it's not made of earth so the Elemental can push on it while gliding.

This seems pretty reasonable, with Str 20 and Large size, it should be within the realm of possibility to brute force an object through the ground, unless the ground is stone or dried clay. e.g. something earthworms can't tunnel through would probably need to be smashed (maybe using the object as a hammer).

For objects not as strong as a ball bearing, this will be very damaging to the object! (As a combat move on a grappled creature, this seems potentially OP, especially burying them alive by stuffing them into the ground. But many Tiny creatures aren't quite as small as a ball bearing or marble, or shaped in a way that would move dirt out of the way. So you might just rule the attempt as a Slam attack unless the ground is particularly loose soil that would make it easy to bury a Tiny creature in, if your fist had no resistance, just the creature Grappled in it.)

Maybe also / instead damaging to the Elemental for a strong and hard object like a ball bearing that could work as a rock hammer in reverse; it might be like trying to drive a nail into wood with your hand. But us puny humans don't have skin like Earth Elementals.

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(The elemental might have a problem with a small stone: once it takes the stone underground, the stone could be considered part of the ground and the elemental might not be able to glide through ground while also pushing on the stone object.)