Thomas is a boy who suffers from Tourette's Syndrome, appearing in the episode "Le Petit Tourette". He has not appeared in any other episodes, and presumably attends a different class or different school to the rest of the South Park kids. He was voiced by Matt Stone.
Thomas's only appearance as of yet sees him giving Eric Cartman the idea of faking Tourette's Syndrome, as he sees that Thomas gets away with swearing constantly. After Kyle Broflovski is deemed intolerant of people with the affliction, due to Kyle claiming Cartman to be faking it, he encounters Thomas when attending a meeting for people with Tourette's.
Thomas does believe that Cartman is faking it, and later helps Kyle with a plan to stop Cartman from appearing on Dateline with Chris Hansen so he will receive more attention. Thomas and Kyle contact a number of pedophiles and invite them to the studio claiming it to be their home. Thomas welcomes them in, but upon seeing Hansen, they all shoot themselves, causing the audience to flee thus ruining the recording.
Hansen is angered with Thomas, but he replies with swearing which causes Hansen to leave. Cartman however is happy to have had the show canceled though, as he has lost control of his speech, revealing embarrassing secrets about himself. Craig Tucker then asks Thomas if he can be his friend, as he adores Thomas due to him being able to swear whenever he wishes.
Thomas has a light yellow shirt with green stripes and dark green trousers. He has dark blonde hair and faint bags under his eyes.
Thomas suffers from regular outbursts of swear words, primarily "cock" and "shit," wherever he may be, which is not helped by his mother who tries to integrate him into society when he has a series of outbursts in a toy shop. He also has a very nervous personality, similar to that of Tweek Tweak or Rebecca Cotswolds, and has black rings under his eyes implying he is very stressed and doesn't get much sleep.
He attends the Tourette's Tolerance and Understanding Foundation where there are regular meetings for him and other children with Tourette's Syndrome.
Cartman was faking having Tourette's in order to get away with saying swear words with impunity. After Cartman whispered to Thomas, "Isn't having Tourette's awesome?", Thomas saw through his charade and set out to expose him.
Thomas cooperates with Kyle in stopping Cartman's attempt to get on Dateline to spew anti-Semitic and vulgar messages on national television, agreeing that Cartman was faking the condition and giving people a negative impression of people affected by Tourette's.
Craig Tucker seemed to think Thomas was very cool for being able to swear whenever he wanted. At the end of the episode, he asked him, "Could I just like, hang out with you sometime? Like, do your laundry maybe?" However, the pair have not been seen together since, nor has Thomas been seen at South Park Elementary.