[Nobita...well, going into the sewers is not his favorite thing to do. And while he's met bug people before and they've been quite nice, Webber feels...a bit more feral than the ones he's used to. So naturally he's nervous. That nervousness has resolved itself into several wriggly lines constantly dancing around him, making everything around him tremble. Which only escalates his nervousness.]

Eeek! [He's much less reserved about his reaction to the water changing.] That's not good! That's really bad! What if we get stuck and can't even move? That's even worse than being washed away! [At least if they get washed away they have a chance to get washed out an exit...]