Stories tale of a beast with a thousand mouths. Each greedier and hungrier than the next. At least that's how the tale's used to go. Nowadays, they're called the under-folk. In the early 90's scientists discovered that under the right conditions a wormhole would temporarily breach the surface of reality under children's beds. The exact conditions are still under investigation, but generally, they were consisted of low-light environments, concrete housing foundations, and the most important ingredient of all fear of young children. The wormhole would last no longer than 5 minutes, typically about three-and-a-quarter minutes, but in that time the under-folk would cause mischief such as stealing laundry, causing bumps in the night, and generally terrifying children to extract the terror from the youths' hearts. Generally, the scientists studying this phenomenon thought the process was never harmful to the children, hence the dozens and dozens of test subjects that had involuntarily been the subject of a dozen government-funded research programs. Unfortunately, that all changed with the 13th experiment.

Experiment 13 consisted of a standard observing period in a small commuter town outside of Boston. The child in question was 8 years old, and had a tendency to sneaking into the family living room after his parents had gone to sleep to watch scary movies on Netflix. The subjects were typically randomly selected, based on a geographical region, in this case a 50-mile radius around Boston, MA was selected. This was to prevent bias in the experimental data. The experiment started off normally, the setting up of monitoring equipment during a routine house inspection, the monitoring of the feeds outside in an unmarked van. What they didn't expect was the scream at 2:12am -- a scream that shattered windows, the current scientific understanding of the under-things, and their grant funding...