Rope Trick Bunker of Doom

Rope Trick (Transmutation)
2nd Level Transmutation
Casting Time: 1 action
Components: V, S, M (powdered corn extract and a twisted loop of parchment)
Duration: 1 hour per CL

You touch a length of rope that is up to 60 feet long, one end of the rope then rises into the air until the whole rope hangs perpendicular to the ground. At the upper end of the rope, an invisible entrance opens to an extra-dimensional space that lasts until the spell ends. The extra-dimensional space can be reached by climbing to the top of the rope. The space can hold as many as eight Medium or smaller creatures. The rope can be pulled into the space, making the rope disappear from view outside the space. Attacks and spells can't pass through the entrance into or out of the extra-dimensional space, but those inside can see out of it as if through a 3-foot-by-5-foot window centered on the rope. Anything inside the extra-dimensional space drops out when the spell ends.

Why is this a big deal

The spell creates a 3'x5' extradimensional space, centred on the rope, so it can be used to bypass thin doors and walls. The bigger use of this spell is to create impenetrable rest areas that require neither guards nor sleeping shifts, and which allow for parties to stop, prepare, and plan, even in the middle of an enemy's invincible doom fortress. The extradimensional space holds 8 people by default and lasts long enough for a full-night's sleep at 8th level (or 5th level with Extend Spell feat to use up a 3rd level spell slot), meaning the only difference between this and Magnificent Mansion is that this doesn't have butlers or food by default - and this is a 2nd Level Spell.

And then there's ambushes. The spell is dismissable, players inside the extradimensional space can see out, and the minimum altitude of the window is only 5 feet up. The party could arrange themselves in battle formation inside the space (assuming there's somewhere to stand), wait for an enemy to come by, and then dismiss the spell and apparently drop out of thin air. For higher-level fun, a 5th-level wizard can cast shrink item on a fair-sized boulder (1700 pounds at minimum level, assuming a limestone boulder of just the right size) and cover a party of 5 with feather fall. Now the hapless enemy finds several huge boulders dropping on their head from 30 feet up, followed by a squad of feather-falling adventurers.

Why this may not work

The spell creates a 3'x5' doorway into an extradimensional space. Read that again: your eight people are all hanging from a rope in outer space, with nowhere to get off and lounge. However the spell states you can pull the rope up into the space and the door is closable so they will not simply fall out.

No Fun Allowed

"Anything that can see invisible (don't forget the 2nd level spell) will see the dimensional window you opened. The DM will likely have an ambush waiting for you or if they have had enough of your bullshit, setup an ambush and cast dispel."

"Wait, this is not intentional? Our party has been using Rope Trick as shelter ever since we first started playing."

”Nothing in the spell says where you appear after it ends. A DM could rule that you appear in front of the hole at the end of the spell, blocking the passage through thin walls. I always imagined that the hole itself spat you out at the end, which could make it harder to set up a proper fighting formation… though not necessarily impossible."

See Also

• 15,000,000 Gold a Day
• Peasant Railgun