Triform transporter
A triform transporter was a piece of teleportation technology. It consisted of three pieces which, when arranged into a triangle on a flat surface, would project a dark surface into the triangle which would entrap anyone standing on it, as well as a handheld trigger switch. Anyone standing atop the portal would then be dropped through it when the device was activated, after a count while the transporter charged up.
The bounty hunter "Rogue" used one to send his targets to an incinerator, which could only hold one person at a time. When he mistook the Fifteenth Doctor for a Chuldur he was hunting in 1813 Bath, he got the Doctor onto the transporter aboard his spaceship, but the Doctor was able to get him to deactivate it by revealing he was a Time Lord.
The Doctor subsequently reset the transporter's destination to a "barren dimension" instead of the incinerator. When he and Rogue set out to find the Chuldur, however, they discovered they were dealing with a Chuldur family of at least four individuals. The Doctor reconfigured the transporter to carry six, its maximum, but the change meant the device would only work once.
The Doctor and Rogue set up two vertices of the transporter to entrap the Chuldur when they prepared to stage a wedding between two of their number, finding out there were five of the shapeshifters when it appeared that the Doctor's companion, Ruby Sunday, had been killed and her form taken by one of the Chuldur. However, when the Doctor activated the transporter portal, trapping the Chuldur, it turned out that Ruby was in fact still alive and had been posing as one of the aliens to save her own life.
When the last Chuldur arrived, Rogue pushed her onto the portal, trapping it at six. The bounty hunter then sacrificed himself by taking the trigger and switching places with Ruby before activating the transporter. Rogue asked the Doctor to find him before he and the Chuldur were banished. However, the sheer number of other dimensions to which he could have been sent made the search difficult. (TV: Rogue [+]Loading...["Rogue (TV story)"])
