Quantum Duplication Rift/cleft

First referenced:

The Right Turn

Other References:

'I think I may have missed the end of the world..... {Part ??}'

First encountered by the unnamed author, Chris and Caitlin in a rugged, rural location, the rift has the unusual property of duplicating lifeforms which enter it, based on the decision to go either left or right at a particular split within the structure of the cleft. Rather than going either left or right, the lifeforms would be split, with one copy going left, the other going right. Those that took the right path would promptly exit the cleft, while those that took the left path would exit some hours later.

While benign by itself, a dangerous, intelligent carnivorous entity not dissimilar to the Silver Nooses was apparently using the rift to capture the left path duplicates, taking them to a cave for later consumption.