Bookworm

The Bookworm (voiced by Richard Kind) is a minor antagonist in Toy Story 3. He is a green worm with glasses and a sturdy flashlight. He is a genius who loves reading books.

Role in the film
Bookworm is an intelligent worm toy with a built-in flashlight.

He keeps a "library" of sorts in a closet at Sunnyside Daycare which holds instruction manuals for many different toys, including Buzz Lightyear. He gives Lotso a manual to reset Buzz, allowing Lotso to make Buzz one of his cohorts.

Later, after Bookworm hands "Spacesuit Ken" (unaware that it's really Barbie in disguise) a Buzz Lightyear manual, he reacts with disgust when he discovers that "Ken" is actually wearing high heels.

After Lotso is removed from Sunnyside, it can be implied that Bookworm has been convinced of Lotso's treachery, so he reforms, as with the case of the other Sunnyside toys who have previously served Lotso. During the film credits, Bookworm is seen happily using his flashlight to illuminate a disco ball when a disco is being held in the Butterfly Room.

Toy Description
From Official Website:

"Story time becomes extra special when Bookworm joins the fun! This bedtime reading companion encourages your children's love of reading, while keeping them company with his happy smile. Bookworm's sturdy purple flashlight features an extra-long-lasting light bulb, bright enough to read by without causing eyestrain. Two C batteries included. Ages 4 and up."

Trivia

 * Bookworm appears to have been based on the Glo Worm toys of the 1980s.
 * His glasses are somewhat similar to Mr. Skipperdoo's.
 * Lotso seems to disapprove, if not dislike,  of him. This can be seen after he tosses Buzz Lightyear's manual at his feet, Lotso gives him a somewhat a disapproving glance. This may also imply that Bookworm did not enjoy being one of Lotso's gang and Lotso was aware of it.