When Dipper's group finds it they realize that the society has been removing the whole town's memories every time something supernatural occurs.
After a minor struggle between the groups, Ivan is in range to wipe everyone's memories.
Mc Gucket jumps in front of Dipper and takes a full blast, but it has no effect on him as his mind was damaged long ago.
As an added benefit as a member of the society, they also use the gun to erase other unpleasant memories and troubles on themselves.
The leader of the cult, Blind Ivan, then intends to use the gun on the children, but Mc Gucket appears and rescues them.
Further memories show that he created the Blind Eye Society and subsequently became addicted to the effects of the memory ray, continuing to wipe his memories for every disturbing incident, problem, and mistake he came across rather than face his experiences, warping his mind a bit more each time.
His overuse of the ray gun caused his mind to deteriorate until he had become insane, unable to remember anything from the last thirty years.
The ray gun used for the process stores the removed memory in a glass tube which is then sent to "The Hall of the Forgotten" via a pneumatic tube.
Once the meeting adjourns, Dipper, Soos, and Mc Gucket go in search of the memory cache in the Hall, while Wendy and Mabel stay to make sure the society members don't return.
But Mabel is more focused on a message she just received from her former crush and pen pal, Mermando.
However, she is devastated to learn that he is to be wed in an arranged marriage to the Queen of the Manatees in order to prevent an undersea Civil War.
Before she can use a payphone to report the strange phenomenon she's just witnessed, a robed man appears from nowhere and drags her away screaming into the night, while the gnomes proceed to steal her pie.