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Comments: 12
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Rating: 3.4167
Condition: Normal
ID: 6129


September 14, 2010, 11:18 am

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Recursive Portal Trap


Now you're DMing with Portals!


"You enter the hallway. About thirty feet away behind a pit, a goblin jeers at you, pulling out a bow."

"I shoot my longbow at the goblin."

"Your arrow flies towards the goblin, but disappears before it hits."

"I shoot again."

"Your arrow disappears as before. From behind you, an arrow strikes you in the back."

"I try and see where the arrow came from."

"It's one of yours."


The dual portal trap is set up as follows:


Portal (1), open space (O), second portal(2), pit or other hindering terrain a monster can hide on the other side of (X), and then a hostile monster with a ranged attack (M)

Ranged attacks entering either portal disappear, coming out of the opposite portal the next round. Portals release projectiles towards the opposite portal, meaning that ranged attacks can indefinitely move between the portals. The magic of the portals actively aim projectiles at any creatures in the area between the portals. The portals only affect ranged projectiles and magic, and creatures pass through them with no effect. If a monster tries to attack the party from the far end of the trap, their projectiles are caught by the portal, and then used to attack by the opposite portal. (For example, Monster M shoots at the blank space (O). His projectile disappears at portal 2, and then comes out of portal 1, aimed at any creature in the blank space, towards portal 2.)


The portals can be defeated through various methods:
Dispel spells, merely exiting the affected area of the trap, and bypassing it entirely. A group that makes no ranged attacks through the portals is in no danger from their own attacks.

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Comments ( 12 )
Commenters gain extra XP from Author votes.

Voted Pieh
September 14, 2010, 14:24
Short and sweet. Makes me want to map out an incredibly complex portal trap dungeon of some mad spacial warping abomination. Hm. Possibly some sort of giant flying lizard that craps alternating recursive portals everywhere.

Guide: "Don't step in that!"
Hero 1: "Ew, some sort of-" *Disappears*
Hero 2: "Where did he go?"
Guide: *Points up*
Hero 1: *Falling from a excrement portal on the ceiling"
September 14, 2010, 16:43
Another possibility is that the trap is already filled with projectiles loosed by previous victims of the trap- a whirling river of arrows, bolts and magic still hurtling down the passage.
September 17, 2010, 18:22
I don't know about this. Unless the portals add some sort of "push" to an object when it exits, most normal projectiles will eventually slow down and stop. Even magic projectiles might fissle out, given enough time, and some of those (ie fireballs) are probably subject to the same air friction as normal missiles anyway.

The "one over, one under" configuration would still work like this, though.
Voted Cheka Man
September 14, 2010, 19:05
A nice orginal little trap.
Voted EchoMirage
September 17, 2010, 7:08
Actually, two linked portals can be placed below each other. The lower one covers a shallow pit with something desirable. Once you go in, you fall - from the upper portal into the lower one, and again and again and again... until you are rescued, or die.
September 17, 2010, 9:06
Or you get pushed out of the effect through magic, psionics, ect.
September 17, 2010, 17:09
Don't forget - if you are pushed out later, not right away, you still will have quite a velocity, some 50m/s :D
Cheka Man
September 17, 2010, 18:51
If you fall for too long, not even grabbing onto a rope would help you, as your velocity would snap it.
September 24, 2010, 19:56
A levitate, fly or similar effect, magic or psionic, could get you out of the process of constant falling.

Plus, I'd see the dungeon "owner" needing to maintain the trap to keep it free of debris and mice and other stuff (read corpses). Alternatively, the magic of the portals could just teleport stuff somewhere else after some time of falling.
Voted herrozerro
November 2, 2010, 9:50

only voted

Voted Fishy2099
February 21, 2013, 12:57
A great idea
Voted valadaar
January 15, 2015, 15:23
Great stuff! Feels like it would be perfectly at home in Grimtooth's traps...


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       By: Yokima.van.zephrill

Tämbourine is firmly placed on my back ,to unsheathe this sword I simply have to say "re clouse" meaning come to me or i can just reach over and unsheathe it the old fashioned way. This sword was created to my liking tambourine is made of raw-like metals I found in different regions as I begun to forge the metals together, I’ve noticed that the raw metal materials were different pieces to a wide variety of swords that were used the past and present, being so most blades have a sheer grey texture Tambourine’s blade became black as the depths of the oceans. The blade expands to 6” which weighs 426lbs the sapphire jewel placed on the tip of hilt (upper middle center of the base) it emits a aura texture of purple which weighs 24lbs the jewel is un-breakable it negates magic for tambourine has a mind of its own only belonging to me it finds a worthy opponents who doesn’t use magic or any type of power to their liking which I can agree with(who would want an opponent that abuses their powers to kill for no reason or to avoid dying by honor tambourine fights with honor and accepts its glory or defeat) I’ve named the sapphire Sophia because not only that its rare and radiant it resembles my burning passion for my love Sophia. I made the hilt to be a length of 15 inches its frame is created with fine katchin (very thick and heavy metal) it alone weighs 50 pounds its texture is black like mixture of, I made it to be a cruciform hilt so it has room for two hands. I I made the blades hilt aprox. 2”, the blade is double-edged but the left side of the swords frame can block and or negate ones attack if needed, it weights 500lbs making it nearly unmovable. To go up against this sword is to quickly find your own death. Tambourine is a twin sword to Terra.

Ideas  ( Items ) | February 20, 2010 | View | UpVote 1xp

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