The Spiffies first appeared in "Animal Testing", Adam was transferred to their class, and right off the bat, they were guns-a-blazing, lashing out at Adam not being as intelligent as the rest of the class, before he proved his genius, and won their respect. Adam joined them in the school spelling bee, but soon backed out, being afraid of losing his old friends. Shortly afterwards, Jake got transferred to their class and went through the same process.
They returned in "Law and Odor", running the school courtroom. They were still mad at Adam for losing them the spelling bee in the last episode (and it was likely Jake did the exact same thing). So, out of bias, they sentenced Adam and Jake to a week of community service, working as hall monitors.
- Phineas Porpoise - A bottlenose dolphin, who's the most outright and quick to judgement of the group. He's been agrred upon as the one who takes charge of the other four, and as the leader, he calls the shots, telling The Spiffies what they'll be doing and what the rules of their role-playing fantasy games are.
- Marvin Hammy - A sweaty, snot-nosed pig, and the weakest link of the group, unbeknownst to the others. He's not an idiot, he's just not as much of a genius as the others. However, he's still second in command.
- Aloysius Elephant - A nerdy elephant and teritary member of the team. As the biggest member, he's considered the group's muscle, which only goes so far, considering it's the muscle a pack of frail and scrawny nerds. He is generally the only with the responsibility to push Daniel around, given he's the only ne (who's not the leader), who's big enough to do so with ease.
- Daniel Calamari - A sepiothius squid and quaternary member of the team. He is always in a cylendrical fish tank, that is pushed by other Spiffies (mostly Aloysius), to keep him in motion. He's unable to breathe outside of his tank and can only speak, by blowing bubbles, which when popper, release singular sylables of his speech. Ironically, despite being aquatic, he suffers from major sea sickness and can't ride on boats. This may also be why his only contact with water is his concealed, fine-tuned fish tank, which he uses as a "land student" as opposed to a student in the school's underwater wing.
- Nestor Parrot - An electus parrot and quinary member of the team, with a long list of medical disorders, allergies, and diseases.
- Animal Testing
- Law and Odor
- My Science Project (Only Phineas)
- Guano in 60 Seconds (Cameo)
- I Got a New Aptitude (Cameo)
- Jake's Day Off (Only Phineas; Mentioned)
- Carny Crazy (Only Phineas, Marvin and Aloysius)
- Making the Grade
- Pants in Space
- The Big Field Trip Part 1 (Cameo)
- The Spiffanos
- Diplomatic Insanity (Only Phineas)
- That Darn Platypus
- Pride and Pixiefrog
- Shark Fin Soupy (Only Phineas)
- Animal School Musical (Only Phineas and Aloysius; Cameo)
- Knights of the Multiplication Table
- Wild Thing (Cameo)
- All five of The Spiffies belong to species, which, in real life, have proven extremely advanced levels of intelligence. Dolphins, pigs, elephants, squids, and parrots have all been considered a few of the most intelligent, non-human animals on Earth.