Mr. Jones

Mr. Jones is the secondary antagonist of Toy Story of Terror!.

Personality
Though he is an iguana, Mr. Jones acts more like a dog. He follows his training by his master Ron closely, even inadvertently exposing his toy-napping scheme to Bonnie and her mother by doing so. His loyalty to Ron, however, is presumably discarded when he is sent to the iguana sanctuary and thus no longer has any animosity for any toys that he used to abduct for his owner.

Toy Story of Terror!
Mr. Jones is a pet iguana owned by Ron, the manager of Sleep Well. Ron trained him to retrieve toys from visitors and bring them to his office, where he placed them in a basket and rang a bell to alert Ron.

When Bonnie Anderson and her mother arrived at the hotel for the night, Mr. Jones, after a period of time, brought the entire toy gang along with Combat Carl and Jessie (whom Mr. Jones found hiding behind a shower curtain that he slashed with his claws), eating one of Mr. Potato Head's arms in the process. After Mr. Jones rang Ron's bell to alert his owner of his success, Ron praised his pet lizard before locking Jessie in a cabinet with the other stolen toys.

Mr. Jones then proceeded to rest until he saw Jessie (who managed to escape) sneaking toward the curtain hiding Ron's scheme. He attacked her, but after she noticed Mr. Potato Head's arm and Combat Carl's hand (which Mr. Jones had eaten sometime before the main events of the story) in the back of his mouth, she kicked the lizard's stomach, forcing him to cough up Combat Carl's hand, then pushed her head and arm inside his mouth, retrieving Mr. Potato Head's arm before escaping.

With the help of Mr. Potato Head's arm, Jessie tricked Mr. Jones into yanking off Ron's curtain, revealing his scheme to Bonnie and her mother. After Jessie froze because of the presence of the humans, Mr. Jones retrieved her and brought her to the basket before ringing Ron's bell, further exposing his owner. Later, Ron fed him with a dog dish, which he proceeded to eat, just as two police officers arrived to arrest his owner for theft. It is unknown what happened to him afterwards, though according to the commentary on the DVD, he was to be sent to live in an iguana sanctuary called Iguanaland. His further fate is unknown though it's possible that upon entering the place that he lived better and redeemed himself.

Trivia

 * According to director Angus MacLane, Mr. Jones has a missing scale on his left breast, in allusion to the great dragon Smaug from Tolkien's The Hobbit. Incidentally, a film adaptation of The Hobbit featuring Smaug was released around the same time as Toy Story of Terror!.
 * He bears some resemblance to Daisy's pet iguana Knuckles from Quack Pack in both appearance and personality.