Alright, well... it was a large mushi - or maybe a colony of smaller ones, I couldn't say for sure - that had settled into the bottom of an ocean trench. It was nocturnal, but usually stayed hidden deep in the ocean, since moonlight was enough to bother it, so it waited until cloudy nights to emerge and hunt.

On those nights, it would use its tendrils to snare passing animals and pull them into itself; from there, it would... for lack of a better way of putting it, it seemed to eat the time they had lived for. I can only speculate as to the process, but it would also seem to break the bodies of its prey down into a number of genetically identical embryos, which it would store up during the month. Each full moon, the mushi would release those embryos as waste in... let's say a few hundred globules, as an estimate, where it packaged them together.

Furthermore, those packages had another odd property: If one of those globules was consumed by a female relative of one of the embryos held within, the embryo would make its way to the uterus and - in a fraction of the animal's standard gestation period, if the human examples were anything to go by - would develop into an infant physically identical to the original who was eaten by the mushi. Though, they didn't retain any of the original's memories.