How does Mark respond when he encounters the Toad in Chapter 16? How is the Toad's behavior described?

Mark scrambles to his feet, wakes Trina, and pulls her back. He shouts for Alec and Lana to wake up. Lana questions Toad about Misty, but Toad wants help getting the things out of his head. Toad reveals he held Misty and kissed her head and watched her die, after which the bugs crawled from her and into Toad’s head.