Alliterative title, simple question, probably a complicated answer.
Can you link multiple instances of Magnificent Mansion together? For example, if two casters cast the spell simultaneously, could they reasonably create a single Mansion with 100 available 10ft cubes and two entrances?
My cursory google search didn’t turn up anything that expressly forbids this, so I wanted to get other people’s thoughts on the matter. Other than allowing instantaneous travel between two points for 24 hours (at the cost of two 7th level or higher spell slots, mind you), are there other ways that this use breaks the game and/or should absolutely not be allowed?
If you wanted to double-cast Magnificent Mansion just to have extra space, you could conceivably cast one inside of the other, though it would be two distinct instances, rather than a combined volume to manipulate. I assume that once the primary mansion expires, the door of the second would essentially takes its place on the material plane, though it isn't explicitly stated. (In the same way that any creatures are automatically dumped out.)
The downside to Demiplane, (which is probably discussed in Lyxen's link), is that it requires a casting to travel between previously created demiplanes, and if you stay longer than an hour, it's entirely possible to get yourself stranded, unless you have another method of Planeshifting back to the Material Plane.
For teleportation shenanigans, the spell Teleportation Circle can be permanently affixed to essentially any horizontal surface that can support it, including moving objects , like a ship. Supposedly, if the surface is light enough, you could then cast Teleport on yourself while carrying the TC circle to some other location. As a DM, I'd be watching that very cautiously.
Jeremy Crawford specifically addressed Teleportation Circle with SageAdvice, saying that "ground" was meant to apply broadly to a [walkable] surface, not a fixed point in space.
I whole heartedly agree that this can lead to problems, but I think the 10ft diameter circle is probably the better restriction to lean on. It requires the area of a standard room, so making it sturdy and light enough to "carry" without breaking could be difficult.
As long as the TC can't be rolled up on a rug, (or otherwise significantly bent), then it'll have a hard time going through doorways or being toted around.
It also takes a full year of casting daily to make permanent, so if a DM gives players that much downtime, they know what's coming.
I agree. Anything that can be deemed an "object" probably shouldn't qualify as "ground" for the purpose of Teleportation Circle, however, there are consequences if we don't recognize that as an exception. For example, the spell Earthbind states:
"An airborne creature affected by this spell descends at 60 feet per round until it reaches the ground or the spell ends."
So any non-ground interposing barrier would technically force the creature to continue to descend for 1 minute, which would be non-sensical if it landed on something like an airship, or an immoveable rod, and those things weren't counted as "ground". (Would Earthbind cause an airborne creature who landed in the ocean to continue to descend, or does water count?)
Basically, "ground" should functionally mean a surface which effectively prevents further movement. (Relative to something, presumably gravity.) A carpet wouldn't count because if you landed on it in the air, you would simply drag it with you.
If you want to use "ground" to mean "earthen material", then the players might fill a wagon with dirt to achieve the same effect. (In such a case, I would defer to the description of Detect Magic for a rough guideline. That is, "ground" would constitute dirt at least 3ft thick. So, a teleportation circle would require 300 cubic feet of dirt [27,500lbs] {or possibly 4,000lbs of iron}. Though, that's just a homebrew guideline.)
If you want to literally mean the "surface of the earth", then casting it on grass and then cutting the sod might still qualify. The surface hasn't change, other than through its attachment with the earth beneath it. [Insert question about casting similar spells underground.]
Or, perhaps a Druid could use Move Earth to transport a teleportation circle without ever disconnecting it from the "ground".
What if you cast the first MMM, then entered it and, at the entrance, cast so the other MMM's entrance was exactly lined up with the first one's. So you could walk from one to the other.
If the objective is to cast two mansions thousands of miles apart, link them, and be able to enter one in one city and exit the other in a different city ... I would say no just ruling as a DM. It is a creative idea but it isn't the point of the spell.
On the other hand, if two high level spell casters wanted to stand side by side and create a double sized mansion with front and back doors so they could host a particularly large party ... I might allow if just from a fun perspective ... but such applications would need to be limited ... perhaps the entrances would have be linked within a foot of each other or something similar. Being able to link two mansions should not create a way to link two locations in space to bypass walls or other obstacles. This is the main issue with allowing creative uses of spells in some cases for fun, they can suddenly acquire some other interesting applications that I might prefer not to allow.
Alliterative title, simple question, probably a complicated answer.
Can you link multiple instances of Magnificent Mansion together? For example, if two casters cast the spell simultaneously, could they reasonably create a single Mansion with 100 available 10ft cubes and two entrances?
My cursory google search didn’t turn up anything that expressly forbids this, so I wanted to get other people’s thoughts on the matter. Other than allowing instantaneous travel between two points for 24 hours (at the cost of two 7th level or higher spell slots, mind you), are there other ways that this use breaks the game and/or should absolutely not be allowed?
Thank you, good to know!
If you wanted to double-cast Magnificent Mansion just to have extra space, you could conceivably cast one inside of the other, though it would be two distinct instances, rather than a combined volume to manipulate. I assume that once the primary mansion expires, the door of the second would essentially takes its place on the material plane, though it isn't explicitly stated. (In the same way that any creatures are automatically dumped out.)
The downside to Demiplane, (which is probably discussed in Lyxen's link), is that it requires a casting to travel between previously created demiplanes, and if you stay longer than an hour, it's entirely possible to get yourself stranded, unless you have another method of Planeshifting back to the Material Plane.
For teleportation shenanigans, the spell Teleportation Circle can be permanently affixed to essentially any horizontal surface that can support it, including moving objects , like a ship. Supposedly, if the surface is light enough, you could then cast Teleport on yourself while carrying the TC circle to some other location. As a DM, I'd be watching that very cautiously.
Jeremy Crawford specifically addressed Teleportation Circle with SageAdvice, saying that "ground" was meant to apply broadly to a [walkable] surface, not a fixed point in space.
I whole heartedly agree that this can lead to problems, but I think the 10ft diameter circle is probably the better restriction to lean on. It requires the area of a standard room, so making it sturdy and light enough to "carry" without breaking could be difficult.
As long as the TC can't be rolled up on a rug, (or otherwise significantly bent), then it'll have a hard time going through doorways or being toted around.
It also takes a full year of casting daily to make permanent, so if a DM gives players that much downtime, they know what's coming.
I agree. Anything that can be deemed an "object" probably shouldn't qualify as "ground" for the purpose of Teleportation Circle, however, there are consequences if we don't recognize that as an exception. For example, the spell Earthbind states:
So any non-ground interposing barrier would technically force the creature to continue to descend for 1 minute, which would be non-sensical if it landed on something like an airship, or an immoveable rod, and those things weren't counted as "ground". (Would Earthbind cause an airborne creature who landed in the ocean to continue to descend, or does water count?)
Basically, "ground" should functionally mean a surface which effectively prevents further movement. (Relative to something, presumably gravity.) A carpet wouldn't count because if you landed on it in the air, you would simply drag it with you.
If you want to use "ground" to mean "earthen material", then the players might fill a wagon with dirt to achieve the same effect. (In such a case, I would defer to the description of Detect Magic for a rough guideline. That is, "ground" would constitute dirt at least 3ft thick. So, a teleportation circle would require 300 cubic feet of dirt [27,500lbs] {or possibly 4,000lbs of iron}. Though, that's just a homebrew guideline.)
If you want to literally mean the "surface of the earth", then casting it on grass and then cutting the sod might still qualify. The surface hasn't change, other than through its attachment with the earth beneath it. [Insert question about casting similar spells underground.]
Or, perhaps a Druid could use Move Earth to transport a teleportation circle without ever disconnecting it from the "ground".
What if you cast the first MMM, then entered it and, at the entrance, cast so the other MMM's entrance was exactly lined up with the first one's. So you could walk from one to the other.
If the objective is to cast two mansions thousands of miles apart, link them, and be able to enter one in one city and exit the other in a different city ... I would say no just ruling as a DM. It is a creative idea but it isn't the point of the spell.
On the other hand, if two high level spell casters wanted to stand side by side and create a double sized mansion with front and back doors so they could host a particularly large party ... I might allow if just from a fun perspective ... but such applications would need to be limited ... perhaps the entrances would have be linked within a foot of each other or something similar. Being able to link two mansions should not create a way to link two locations in space to bypass walls or other obstacles. This is the main issue with allowing creative uses of spells in some cases for fun, they can suddenly acquire some other interesting applications that I might prefer not to allow.