Nnewts: The Battle for Amphibopolis is a graphic novel by Doug TenNapel and published by Scholastic's Graphix imprint.
The fate of all Nnewts hangs in the balance! Herk, falling under the influence of Blakk Mudd, is slowly turning into a Lizzark and abandoning his Nnewt friends. Herk's siblings, Sissy and Zerk, have been corrupted by evil and the Lizzark army is still threatening Amphibopolis with total destruction. Now the Nnewts need a true hero to step up and save the day before it's too late!