Is escaping from a cage-shaped Forcecage really as ridiculously easy as it seems?

Question

The spell Forcecage allows you to create a prison in the shape of either a cage with bars, or a closed box.

Escaping the Forcecage is (obviously) meant to be difficult:

A creature inside the cage can't leave it by nonmagical means. If the creature tries to use teleportation or interplanar travel to leave the cage, it must first make a Charisma saving throw. On a success, the creature can use that magic to exit the cage. On a failure, the creature can't exit the cage and wastes the use of the spell or effect. The cage also extends into the Ethereal Plane, blocking ethereal travel.

However, if you choose the cage shape, it is ridiculously easy to escape, using one of the following means:

• Wildshape into an form that can squeeze through 1/2 inch gaps
• Polymorph, True Polymorph, Mass Polymorph, Shapechange or Animal Shapes, similar to Wildshape
• Gaseous Form, can squeeze through any gap. Maybe also Wind Walk, but that spell doesn't explicitly mention being able to squeeze through gaps.
• Antimagic Field: Forcecage is only immune to Dispel Magic, not Antimagic Field. Would also work on a box-shaped Forcecage.
• Disintegrate, which can destroy creations of magical force. Would also work on a box-shaped Forcecage.
• Casting Misty Step a bunch of times, since it's just a 2nd-level-spell and you're likely to suceed on the Charisma save eventually.

So, in the end, Forcecage with its cage shape seems like it's most likely a waste when used on a caster, especially a druid. Do note that Antimagic Field and Disintegrate are included not because they are especially easy, but for completeness, and to illustrate the wide variety of ways that one can escape a cage-Forcecage.

Is escaping from it really as ridiculously easy as it seems? Or am I missing something?

Answer 1

It's not easy, but you can escape quickly if you have the right tools.

The phrase "a creature inside the cage can't leave it by nonmagical means" doesn't mean you can just turn yourself into a mouse/gas/etc and move out. Walking or flying are mundane movement, even if it was magic that gave you a fly speed or changed your physical size. Your method of leaving must itself be magical, which means it's basically going to be teleportation or planar travel, so you're up against the save. That excludes the "easy" methods of gaseous form or wild shape, polymorph, etc. as escape routes.

Sure, you can spam misty step to get out sooner or later, but that does require you to know the spell (and have it prepared, if that's a thing for you), and potentially burn a bunch of spell slots and waste a bunch of turns, just to escape from one spell. I don't call that "easy". Simple, if you have the proper tools at hand, but costly. (I'm making that distinction in the same sense that walking up a mountain is simple, but not easy.) There are a number of "save or suck" effects that give you another try at the save every turn, but unlike forcecage most of them don't cost you spell slots every time you try. But yes, trapping a powerful spellcaster inside a forcecage is probably not your best use of the spell.

Antimagic field is a sure-fire escape method, from inside or outside, but escaping a 7th level spell by casting a very specific 8th level spell is a very high cost indeed. You only get one 8th level spell per day, ever, so burning that merely to escape a forcecage is a hefty price -- and again, you have to have that AMF spell prepared already, or available through some other method, like a spell scroll.

Disintegrate seems like it would work in this case, whether the caster is inside or not. A forcecage is specifically a "prison composed of magical force", and disintegrate can target a "creation of magical force", so it's a valid target, and it "automatically disintegrates" a ten-foot cube out of a creation of force that's Large or larger. I can't see any reason a disintegrate spell would not work to open a hole in a forcecage. That said, again, you're defeating a 7th level spell with a specific 6th level spell, of which you only ever get 2 per day. While it's not as uncommon as an antimagic field, it's still a significant cost that the party may not have access to. There are many such pairs of spells where one can specifically counter another.

Answer 2

It's only easy for a high level caster.

Besides that, most people just don't have the capacity to do much against it. If you're a fighter, maybe you've got a cloak of the mountebank that has one shot to try to teleport out. If your save fails, well you're done. Polymorph, as others have stated, won't help you because your means of escape isn't magical, you're using mundane movement, so it's the same as just hasting yourself and trying to walk out.

Forcecage is without a doubt one of the most powerful spells in 5E. You're forgetting that the most common enemy you're going to face isn't high level casters, but rather monsters. The spell will almost outright win you most monster encounters. 5E monsters aren't 3E monsters. Save for a number of exceptions you can count on one hand, they don't have extensive spell-casting capability. They're not tossing out disintegrate and most can't teleport. So that means you can effectively take a deadly encounter, forcecage half the opposition and make it a cakewalk and there's likely nothing the enemy can do about it. Honestly, it's one of the cheesiest spells in the game. If your DM doesn't specifically plan for it each and every major battle, it's essentially the "I win" button.

Granted, it's probably not the best spell for NPCs to use against players, but it's insanely good for the PC wizard against monsters and NPCs.

Answer 3

You're exactly right

Firstly, let's define what it means to escape from the force cage using magically means. This translates to you having used magic to facilitate the escape. So the two questions we need to ask ourselves is

1. Was magic actively used in the escape?

2. Was magic actually needed to make the escape possible?

If your answer was yes to both of these questions, the means of escape was magical. If your answer was no to either of these questions, the means of the escape was not magical.

Some other answers claim that "a creature inside the cage can't leave it by nonmagical means" translates to: that the means of escape have to seem magical to the players of the game in all context's. This however involves homebrewing what is considered to be magical because sage advice has already listed what is considered to be magical officially in-game. If you look at the Sage Advice Compendium under the monster section you'll find the question "Is the breath weapon of a dragon magical?". The answer to this question states:

Ask yourself these questions about the feature:

• Is it a magic item?

• Is it a spell? Or does it let you create the effects of a spell that’s mentioned in its description?

• Is it a spell attack?

• Is it fueled by the use of spell slots?

• Does its description say it’s magical?

If your answer to any of those questions is yes, the feature is magical.

So therefore using wildeshape counts as a magical means of escaping because:

1. The ability states: you can use your action to magically assume the shape of a beast that you have seen before (emphasis added)

2. You wouldn't be able to escape the forcecage without using this magical ability(emphasis added).

This same logic applies to all the other methods of escape you've listed because they are spells and are therefore magical based off sage advice (emphasis added).

From an RAI perspective I think the cage is supposed to be easier to escape from as well; given the mechanical benefits that its size is greater than the box's and that spells can pass through it (while they can't pass through the box). It also makes sense that enclosed cages with holes are easier to escape from than enclosed boxes that have no holes.