- "Morphing power is a wonderful tool. It allows Andalites to pass among many different species. It makes us the greatest spies in the galaxy. But it has an awful drawback. You see, if you stay more than two hours in morph, you stay there forever. You become a nothlit. An Andalite living out his life in a different body."
Nothlit is a word in the Andalite language that describes one who has passed the two-hour morph time limit and has become trapped in that form. It is normally impossible to regain morphing ability afterwards. Two exceptions to this are Tobias and Elfangor, both regaining their forms with the Ellimist's aid. A third is Cassie, whose morphing ability was "jump-started" by the metamorphosis from caterpillar to butterfly, the naturally-occurring morphing 'resetting' the morphing clock. Nothlits who become so by choice are often shunned by Andalite society, accidental nothlits to a lesser degree. The Animorphs at several times have avoided becoming nothlits, but Tobias failed, starting in just the first book, The Invasion.
While evading the Yeerks, Tobias became trapped in the form of a red-tailed Hawk. He was able to regain his ability to morph in #13: The Change, but in this case his hawk form remained his 'default' body. While he was able to regain his human form, this was the result of him being briefly sent back in time to acquire his own past self, with the result that his human body is just another morph rather than his natural state.
Elfangor volutarily became a human nothlit, choosing a life on Earth, under the name Alan Fangor, and being married to Loren, after becoming disillusioned with the war. The Ellimist however returned him to his Andalite body, erasing most traces of his life as a human, and transported him back to the Andalite-Yeerk war.
Cassie became a caterpillar nothlit as part of a deal she made with the renegade Yeerk Aftran 942, but her new form's natural metamorphosis into a butterfly effectively reset the morph time limit, allowing her to become human again.
In an effort to prevent David from exposing their secrets, the Animorphs executed a plan to trap him in the body of a white rat.
The Taxxons who served under Arbron were granted morphing ability by the Animorphs, becoming anaconda nothlits. This stemmed from the desire to end their hunger, while retaining a similar form.
- Applegate has said the word is almost an anagram of "Hilton."