[He'll really have to keep an eye out for any Phantumps and Drowzees now. He hadn't really been paying attention to those --they had been on the water for most of their time, after all-- but whatever is happening right now is pretty unusual, so it is also worthwhile to keep unusual theories in mind.]

Are you near a city by any chance? A proper book might have more information on Phantum or Drowzee behaviour than the pokedex does. [And thus, might have something in there that could either confirm or deny this theory of Newt's] I'd check it myself, but we're still several days out from the next city with a library.

[And considering how tired they all are, they are not making their usual speedy progress.]