Someone who relocates Spiders on all other floors of a build excluding their own... This is so the Spiders can breed and mingle freely amongst unsuspecting victims when they are the most vulnerable and don't have their ANTI-Spider defenses up and running.
When you happen to come across an Eight-legged Spider...and Eight-legged mind you...you simply trap it in some sort of sufficient Spider-carrying device and let it free in a stranger’s room on a different floor than your own. And well, that should suffice as a Arachnid Recolonizer.