I'm not sure, but I think it might be possible to touch it if you're extraordinarily patient and lucky. However, I'm pretty sure you won't be able to do anything with it, since it seems to have no clipping on it, so you can't actually touch it or anything. I've seen it run slightly off straight left, and while I don't recall seeing it actually go through the wall, I believe I've gotten close enough to see it not stop just short of it. I'd say these two quarks suggest that it isn't a normal sprite like a townsperson or a party member (at least after it's surprised, not before), so it can't be surprised or cornered. The game can't react to something it isn't programmed to anticipate, so you probably can't interact with it, either.