Alphys is pretty used to seeing different kinds of monsters, but the things about monsters is that their external appearance doesn't really have to correlate to their internal structure. Since they're made of magic, what they look like doesn't need to be what they do. So who knows what any movements do and are supposed to do-- not her, that's for sure.

She nods along to his description, hands clasped together around her hip. "Well, that's... y-yeah, pretty inconvenient. Maybe the Gods will make some boats if we ask? I wonder if they knew this was going to happen, depending on where we picked."