What happens if an elemental is transported to the Astral Plane?

Question

The party I DM a Princes of the Apocalypse campaign for has recently gotten a second Bag of Holding, and they asked what would happen if they put one in the other. With a successful Arcana check, they learned the description from the DMG (p.153-154) with an emphasis on the following:

Placing a bag of holding inside an extradimensional space created by a Handy Haversack, Portable Hole, or similar item instantly destroys both items and opens a gate to the Astral Plane. The gate originates where the one item was placed inside the other. Any creature within 10 feet of the gate is sucked through it to a random location on the Astral Plane. The gate then closes. The gate is one-way only and can't be reopened.

They immediately saw potential in this as what one player referred to as a "nuclear option" if things got really hairy. Being PotA, this could potentially happen in the presence of an elemental, like Imix or Olhydra. As I tried to prep for this possibility, I read Monte Cook's A Guide to the Astral Plane. On page 20, it is noted that:

More than any other plane, the Astral is cut off from the Inner Planes. The dense, unadulterated intensity of the elements there is the antithesis of the Astral Plane. No elemental can exist on the Astral...

So, if the Bag is placed in the other Bag and the elemental is within 10 feet, will the elemental simply not transported or is it destroyed?

Answer 1

Not by RAW

Monte Cook's A Guide to the Astral Plane was written for AD&D, which is quite far from 5e.

The 5e DMG entry (46-48) for the Astral Plane says nothing about elementals, negative or otherwise, so it's safe to assume that nothing special happens to them there in 5e by RAW: if the Bag of Holding explodes near the elemental, it gets treated just like any other creature and sucked into the gate.

Mixing editions will often lead to contradictory results. For example, the 3.5e book Manual of the Planes has a table on pg. 53 labeled "Astral Encounter," that includes the various types of genies, such as dao, djinn, efreeti. The 3.5 material doesn't specify that genies are elementals (instead, they are outsiders). But, if we're mixing editions like you are, the 5e MM does state that they are elementals. Thus, the 3.5 and 5e material together states that elementals are just fine on the Astral Plane, in the same way that your AD&D and 5e combination states that they're not.

As DM, you have the latitude to make your own rulings, so you can decide that elementals cannot survive on the Astral Plane in your world anyway. However, a ruling is just a ruling, not something that has support from the books. It could be an interesting quest to allow the PCs to essentially trade a boss fight for a "one-way" trip to the Astral Plane, where they would have to find their way back.