My thought is the spider comes up to about knee height and is about 2 feet in diameter. I wanted it to have a mind of it's own and function as a pet aswell as a piece of equipment, and one of the other thoughts I've had is that a lot of the time it would stay on my character's back with it's front legs over his shoulders and it's 3 sets of back legs going under his arms and wrapping around his torso. Anyway, I'm working on a character sheet now.