Canon Foreigner: He only appears in the 1999 series. He was added in because with Hilda and Zelda as teenagers, there was no adult guardian living in the house.
Chuck Cunningham Syndrome: He disappears in Sabrina's Secret Life with no explanation. However, one could guess that he left because by then, Hilda and Zelda were legally adults at that point, and didn't serve a purpose anymore.
Beauty Is Never Tarnished: He gets a rare male version of this very briefly in "Paranormal Pi". When his magic tracker throws him FACE FIRST into a mud puddle, the next shot shows him sitting up. There is mud on his clothes and paranormal hunting equiptment but his hands and face are completely clean.
Berserk Button: Messing with Harvey, especially in "Hexcalibur". Also do NOT upstage him in the classroom and make him feel neglected or else he will turn on you faster than you can say Yandere.
Creepy Child: Despite being essentially a nice guy, a lot of his mannerisms are a bit unnerving. He knows a great deal of the paranormal, subscribes to a strange newspaper, watches horror movies and even demonstrates incidents with inoculations via STABBING himself in the arm (with a spoon but still), has the I.Q of a genius and can apparently pick locks. On top of that he dresses in near-formal attire all the time and covers half his face. And then there's his voice...
Cute Bruiser: In "Hexcalibur", during the fight with Morgana, as Merlin. He makes the Badass Boast "If you mess with my best friend, I'll turn into a huge dragon and then you'll be sorry."
Epic Fail: In "Hexcalibur", as Merlin he was absolutely useless at any form of magic that didn't involve dropping an anvil on someone or himself. "Paranormal Pi", Get's pulled through the air by a magic detector, mistakes a chair for a UFO get's thrown in the mud by aforementioned magic tracker and is the laughing stock of the whole town. Also, let's not forget this little exchange from picture perfect. Sabrina *about the school assembly* "the joys of stamp collecting?" Pi- *with a stamp* "stamp collecting, really? Now that is righteous." *gets stared at* "what? You disagree?"
Genius Ditz: Sabrina even described him as "totally smart and really out of it at the same time".
Manipulative Bastard: Not in the evil sense, but he pretty much pulls this on Harvey in "Nothin' Says Lovin' Like Something from a Coven" to get Harvey to pull a break-in and scare type Halloween prank with him. (Although this can be pretty scary if you consider he might be doing this off-screen and what he could smooth talk Harvey into doing, although this is Pi we're talking about.)
Punny Name: Pi is a mathematical term and Pi himself appears to enjoy math as he speaks about equations in "Paranormal Pi".
Real Men Wear Pink: Pi seems to like pink. In "Paranormal Pi" his sunglasses were pink, at the end of "Wag the Witch" he proudly wore a pink dress and even Merlin's magic in "Hexcalibur" has a tint of pink.
Shorter Means Smarter: He's the smallest of Sabrina's human friends and arguably the second shortest in the whole human pre-teen cast (beaten only by Bernard). He is also a nerdy genius.
Trickster Mentor: He comes off as evil and scary but always left a loophole in whatever Sabrina wished for so she could find a way to fix it when it (inevitably) goes wrong. Though he's tired of constantly being asked.