In the vast database there are a number of entries with no index, each denoted by 'NaN' and a name only. Some helpful soul has decided to give them all indexes, why not, he says. 'Because they are dangerous entities from another dimension, they're not like humans, their motives are unknowable. With indexes they can enter our world.' I explain. 'Oh.' he says, as the being labelled 'Yggdrasil' appears in the room, a huge, tree-like monster, its long root-like tentacles whip around the lab, consuming all the flesh in its path.