I must compliment you. Gargantuan really worked for me as an adjective in this question. I pictured a spider so big that it was holding itself up off the ground, legs against the walls and ceiling around him, his body taking up nearly the entire breadth of the hallway.
Don't worry. With the seasons coming, spiders are just looking for places to hang where they won't drown to death. They probably won't crawl into bed with you or hide in the bristles of your toothbrush.
Of course, if they're three hundred pound hallway blocking spiders, you might want to start looking for a new place to live before the awkward backrubs start.
Short Answer: I want to think that when you saw him, he did that thing that spiders do when they're suspended by their legs, where the body sinks backward, pressing the knees forward like it's about to pounce and murder. That's always totally awesome! Everyone loves a furry ball of malice between having to pee and peeing in your jammies.