Muggles' Guide to Harry Potter/Characters/Trevor

Overview
Trevor is Neville's pet toad, who is forever getting lost.

Philosopher's Stone
When we first see Neville, he is standing on the platform talking to an older witch, apparently his grandmother. It seems that he has lost Trevor.

We are introduced to Trevor by Neville, who looks in to Harry and Ron's compartment on the Hogwarts Express to ask if they have seen him. Some time later, Hermione stops by on the same errand; apparently she has chosen to help Neville in his search. Trevor remains lost until the students are leaving the boats on the shore of the lake under Hogwarts; Hagrid apparently then finds him and asks whose toad this is.

Professor Flitwick had demonstrated making things fly by sending Neville's toad soaring about the classroom.

Neville is apparently trying to catch Trevor again when he overhears Harry, Ron, and Hermione planning how to get through the trap door. Dropping Trevor, he prepares, unsuccessfully, to fight them.

Order of the Phoenix
When we meet Neville in the Hogwarts Express, he is dragging his trunk and holding on to a struggling Trevor. He continues to hold Trevor throughout the early part of the trip, dumping him in Harry's lap as he prepares to demonstrate the defensive mechanism of his prized Mimbulus Mimbletonia. Harry, holding on to Trevor, is drenched with Stinksap.

We see Trevor again as they leave the train; Neville carefully stores him in an inside pocket.

Strengths
Although he is often getting lost, Trevor always manages to get found again. It seems he has some ability to transport himself, as he manages to reach the far shore of the lake before Neville himself does.

Analysis
Trevor seems to be present only to give Neville something else to misplace and worry about. He never appears to have any power save that of getting lost, and later appearing where he would have been if Neville had been able to retain him — for instance, he is lost on the Hogwarts Express, in book 1, but then appears near the castle as the first-years are getting out of the boats.