Can you damage a bag of holding from inside?

Question

An opponent managed to force you into a bag of holding to trap you for a while or to suffocate and kill you.

The interior of the bag is an extradimensional space.

Supposedly, you could pierce a bag of holding in earlier editions, and by that destroy it. Here is the text from D&D 3.5

The bag of holding opens into a nondimensional space […] If the bag is overloaded, or if sharp objects pierce it (from inside or outside), the bag ruptures and is ruined. All contents are lost forever.

Can you pierce the extradimensional spaces' walls from the inside in 5e, thereby destroying the bag and freeing yourself?

Answer 1

Ask your DM.

The description for the bag of holding (and similar items, such as portable hole) does not indicate that the walls of the interior extradimensional space can be breached with sharp objects. As you have observed, the walls could be pierced in a previous edition, so ruling similarly in your 5e game seems reasonable; but as the 5e description omits the explicit description found in the 3.5e version, ruling that it doesn’t work like 3.5e seems reasonable too.

That said, it is worth mentioning that Jeremy Crawford gave his own personal ruling on this question on Twitter:

@JeremyECrawford Bag of Holding: extradimensional space or part of Astral Plane? Can it be pierced/cut/torn from the inside?

The inside of a bag of holding is an extradimensional space, and the bag can be damaged from the inside. #DnD

While this is not an official ruling, it does indicate that the opinion of 5e’s rules designer was that the bag of holding functioned similar to the 3.5 version.

Whatever you decide, the players get to know how it works ahead of time.

I’d recommend the DM and players have a conversation about how they want this to work. The players believing it works one way only to have the DM foil their plans by having it work the other way is a recipe for hurt feelings. And the rules require that the owner of the bag knows how it works. The rules for identifying a magic item state:

The identify spell is the fastest way to reveal an item’s properties. Alternatively, a character can focus on one magic item during a short rest, while being in physical contact with the item. At the end of the rest, the character learns the item’s properties, as well as how to use them.

So whatever you decide for your game, it should not be a surprise to anyone, because the bag’s owner knows its properties.

Answer 2

Possibly, but that might be really bad...

A bag of holding is a pocket in extra dimensional space. Presumabily, the walls of the bag are somewhat tough,to prevent things from poking through and becoming lost or destroyed. But if you make a concerted effort, you probably can punch through the side of the bag.

Now, what happens then? You might look up the effects of putting a portable hole in a bag of holding (or vice versa) or read up on how a bag of devouring works. It has generally been pretty catastrophic regardless of the edition. I would personally rule that they bag is destroyed, along with everything in the bag, lost in the howling nether of the Abyss (or some similar place) forever. That seems to pretty much line up with some of the mentioned descriptions.

There is a Dragon Magazine article in issue 271 about the Ecology of Bags of Devouring in 2nd ed, and it plays with the idea of opening up to other dimensions. Utter destruction or dimension hopping, its up to you.