[Nagito picks up on her tone immediately--much faster than he'd pick up on any other emotional cue, like he's used to having to worry about being in danger--and his eyes soon follow her pointing to their visitor. His expression doesn't change, but an observant eye will see how his muscles tense. He slides his phone back into his jacket, pulling the whole thing toward him, but not removing his hand from the pocket.

Still, he sounds perfectly calm.] Well, there's another reason to try and stop people from falling into the River. That eye stalk is different from the slugs, right? For one, they have two.

[He hasn't seen this creature before, in that case.]