|Hair color||Brown (s1-7; 9)|
Gray (s8; some of 9; 10-present)
|Residence||Rattles' house, Elwood City|
|Book debut||'Muffy's Secret Admirer'|
|Cartoon debut||"Arthur Accused!"|
|Voiced by||Scott Beaudin (s14 (at least) - present)|
Rattles has a tuft of hair sticking out of his red baseball hat, which he always wears backwards. He wears a black leather jacket with two pockets at the front, a pale yellow T-shirt, green jeans and high tops. In the first seven seasons and the ninth season, his tuft of hair was dark brown. For the eighth season, his tuft of hair became gray like the rest of his body. In the tenth season, this change became permanent.
For his alternative outfit, he wears a dark blue T-shirt over a pale yellow sleeved shirt instead of a T-shirt and leather jacket.
There is much confusion as to exactly what animal Rattles is. He so rarely takes off his hat that the producers have actually changed what animal he is multiple times. In "D.W., Dancing Queen," he takes off his hat while dancing and has dog ears. This is interesting compared to "Brother, Can You Spare a Clarinet?," where he sticks his earplugs into the sides of his head. Also, in an imagination scene of "Thanks a Lot, Binky," he has small ears on the top of his head, although they were hidden under a full-body cast, so they could be cat ears. When playing sports, he sometimes takes off his hat and has cat ears, such as in "Arthur the Loser," "Meek for a Week," and "Arthur Cleans Up." In "Whip. Mix. Blend.," he clearly is seen with bear ears.
In early seasons, Rattles started off as a tough, generic school bully. After he got an expanded role in Season 8, he becomes the most consistently antagonistic force in the show, with his directly malicious and petty behavior. However, like his friends, Binky and Molly, he started displaying a softer and more intelligent side, with his own personal hobbies that he (secretly) enjoys.
In the episode "Bugged," he is seen with the other kids at the playground playing marbles. This shows Rattles does indeed hang out with other kids in the school despite being a bully.
He has helped D.W. on a few occasions; in "D.W., Dancing Queen," he and Molly helped D.W. do ballet for a school project after Binky twisted his ankle during practice, both serving as D.W.'s backup dancers. In "D.W., Queen of the Comeback," when the Tibble twins start teasing D.W. over her botched haircut, Rattles tries to come up with good insults for D.W. to use against them, though he thinks their feud is ridiculous and initially suggests to D.W. that she ignore them.
He seems interested in knitting. For example, he is a member of Dr. Fugue's knitting club in "Arthur Unravels." Also, it is mentioned throughout the series, though more recently than before, that he is skilled at sewing.
In "Carl's Concerto," Rattles willingly helped George and Carl rehearse for a children's puppet show, alongside Buster and Binky; he played as Mama Bear in George's "Goldilocks and the Three Bears" play. Although Carl's autism made rehearsals difficult, Rattles willingly put up with it without complaint until the day of the puppet show.
Interestingly enough, he doesn't seem to consider himself a bully or at least does not like the label. In several episodes when other characters refer to him as such he counters by saying that he's just "misunderstood." At several points, he also seems to be smarter than he appears, sometimes using shockingly advanced words to describe or explain something; however, as revealed in "D.W., Queen of the Comeback," he doesn't know the definitions of some of said words, such as "bibliophile," and thinks they make good insults. When Brain offered to do his homework for a month in order to get him to join the Chess Club, he refused by saying that it would deprive him of his education. This could show that like Binky his tough guy personality is just for appearances or to cover up his other hobbies.
- In the episode "The Last Tough Customer," Rattles revealed his dad is in marketing.
- Later in the series, he had a dog called Crusher, who first appeared in "Pet Peeved."
- He is lactose intolerant, as revealed in both "Too Much of a Good Thing," and "Brain's Chess Mess." Eating dairy products gives him gas, and he likes to eat peach-flavored sorbet for dessert.
- In the episode "Whip. Mix. Blend.," it is revealed that his mother is re-marrying and that the twins Ansel and Angie will become his stepbrother and stepsister, respectively.
- In "Take a Hike, Molly," it is revealed that Rattles is afraid of snakes, which inspired his nickname. When he was little, he would cry out, "Ah! It's a rattler!" whenever he thought he saw a snake. His real name remains unknown.
- Main article: Rattles/Gallery