It does make me wonder what draws creatures from not just other timelines, a concept I have had properly hand-fisted down my gullet in wipes past, but from other 'realities'. The separation of which is in the fact that all contained timelines appear to have only set species and rules in them while other realities have entirely separate species and rules. For example, I currently reside on Alternia, roughly 40XX sweeps after the uprising of Her Imperious Condescension, several millenia further after the once-believed-mythic attempted coups of the Signless and Summoner, and some hundred or so sweeps before the era of the hatching of the trolls who are destined to bring Alternia to its ultimate destruction. That is my point of origin. Other timelines share it with subtle differences, other timelines are humans on Earth, but we are all contained under a single multifaceted reality wherein we are the species predomiment and the rules governed. When another reality converges, say 'Toriel Dreemurr' from a reality wherein every contained timeline is filled with variations of a human-monster-darkener facet instead, I can only wonder why. Why is this website capable of breaching a point not even the great 'Game' can breach?
succinctly put. I've been wondering much the same myself. perhaps there is something in the inherent coding of this site that's pierced through all the realities like a sewing needle through stacks of fabric.