I would sit back quietly, ask it how it's day is going and why it entered my house. If it didn't answer, I would guess this new arachnid is, like the rest, non-sentient, and proceed to try to detain it by way of broom and laundry basket. If I can catch it, animal control or something might be able to take it from there, if not, I'd bludgeon it to death and inform someone of the corpse of a new creature in my house. If I can't kill it, it won, and gets to decide the next course of action.
EDIT: to be clear, the bolded "if not" is if I'm not able to catch it.