Thelonious is the secondary antagonist and later an anti-hero of the 2001 DreamWorks film, Shrek, and the 2003 3-D short Shrek 4-D. He is the dimwitted minion of Lord Farquaad.
He appears to be Lord Farquaad's royal executioner within the kingdom of Duloc. He also appears in the Nintendo DS version of Shrek Super Slam as a playable character. Thelonious seems to be not as smart as Farquaad's other henchmen.
He was voiced by Christopher Knights.
In the beginning, he was torturing Gingy (also known as the Gingerbread Man). When Lord Farquaad tried to decide which princess to find and marry, Thelonious told him to pick #3 (even though his fingers say 2).
Thelonious also made an appearance in Shrek 4-D. In this movie, he helped the spirit of Lord Farquaad kidnap Princess Fiona. At the waterfall scene, Fiona fights Thelonious off her raft, but he survives, and Dragon burns Farquaad once and for all. Though Shrek and his friends survived the waterfall by grabbing from Thelonious, who was in turn grabbing from a branch, Thelonious is never seen afterwards. It's completely unknown what became of him, but it could be possible that he could have slipped from Dragon, letting him to fall to his death or to the river back again to be dragged by the waterfall to his death, but it's probably that Fiona and Shrek wouldn't let him to suffer such fate.
The name "Thelonious" is a parody of the word "felonious".