Thaddeus and Thor are two characters from from their self-titled Phineas and Ferb 2009 episode. Thaddeus resembles Phineas while Thor resembles Ferb. Thaddeus also closely resembles Napolean Dynamite with his curly brown hair, glasses, and overalls. Despite resembling Ferb, Thor wears Phineas's type of clothes. Thaddeus and Thor have an older sister named Mandy, who is similar to Candace Flynn as well as Vanessa Doofenshmirtz. Thaddeus and Thor try to outdo Phineas and Ferb in building a treehouse. They are also quite arrogant as they brag to Phineas and Ferb about their building skills (especially Thaddeus). However, Phineas and Ferb win in the end and don't get busted by Candace, as usual.
- Thaddeus is named after Thaddeus the disciple of Jesus Christ whereas Thor is named after Thor the Norse god of thunder.
- Because of the fact that Ferb is Phineas's older British stepbrother, Thor could possibly be Thaddeus's older Norwegian stepbrother because of his name and his blonde hair. Thor could also possibly be from another Scandinavian country such as Sweden, Denmark, Finland, or Iceland.
- While Thaddeus is somewhat similar to Napolean Dynamite, Thor is somewhat similar to Forrest Gump.
- Although it isn't seen or mentioned, Thaddeus and Thor could possibly have a pet with a secret identity, since Phineas and Ferb have a pet platypus named Perry, who is secretly a secret agent.