“What you need is a room full of supergeniuses working around the clock, with a supercomputer and two–no no–THREE highly-trained monkeys.”
Bifford "Biffy" Tawilager Goldstein is a large individual and friend of Lee Ping. He is a regular detentionaire, and gets detention almost every school day.
Prior to series start
As seen on Lee Ping's picture, Biffy unofficially attended Lee's tenth birthday party, as he could be seen outside the window, and peeking in because he smelled vanilla iced cake.
Biffy is stated to be the childhood friend of Kimmie McAdams, the leader of the Glamazons. It is hinted that they also used to date until the 7th grade until a wedge was driven between them when Kimmie went "all girly on him."
When Biffy first attended A Nigma High in the ninth grade he soon discovered that the school wasn't built for big and bulky students like him, as he was constantly knocking people over. During this time he received his first ever detention at the hands of Principal Wurst. Once in the detention room he soon discovered that it was quite possibly the only room in the school with enough room for him and has thusly made it his mission to get into detention every day, except for the one day when the Dudes of Darkness were playing.
Biffy was present with most of school at the Prank. Unlike his acquaintance, Lee Ping, who is forced to spend everyday in detention, Biffy seems bound and determined to do the same, aside for the one time he stayed out of detention to watch the Battle of the Bands competition. He accomplishes his tasks by intimidating other students, most of the time Lee Ping, in order to make sweaters for his cat(s), and later on help Lee on his missions to clear his name. He apparently helps Lee because it reminds him of a spy movie, but ultimately his reasons are his alone. Biffy claims that he knows everything, and if an event were to happen recently he would have instant knowledge of it. 
While in detention he uses his techno-savvy ways to help Lee on missions, including devising methods to track Principal General Barrage and guiding Lee through the school using his cell phone's GPS device. Biffy is also a huge Dudes of Darkness fan to the point that he once broke off his friendship with Lee because he accidentally broke up the band.
Biffy is explained to be one of the many people who are immune to the hypnotic effects of the Prank song, explained to be the result of a simple hiccup in his genetics, like the ability to curl one's tongue. Victoria also seems to be aware of his sewing skills and takes advantage of them by assigning him as the official "Seamtress" of A Nigma High. 
It appears that Biffy and Kimmie's once romantic relationship had been reignited during the time that Kimmie and Biffy ended up in detention together, while Lee had gone to the mall to save Tina from Brandy and Brad Von Chillstein's plot. Kimmie ending the period by telling Biffy to call her.
Biffy continues to aid Lee Ping against Radcircles providing tech support and occasionnally muscle in Lee's endeavors. He has also entered a slowly growing relationship with Kimmie going on a "Not Date" with her at the carnival as well as entering a friendly rivalry with her becoming rival campaign managers during the student elections.
On one occasion Lee suspected him of being Radcircles thanks to spotting him in his tenth birthday photo spying on it from the street, taking advantage to play an elaborate prank on Lee though he did confess that it wasn't him. Biffy also developed a extreme disliking for Camillio Martinez since he asked out Kimmie, reluctantly forgiving him when he learned that he was brainwashed to do it.
Biffy joined Lee in the underground labs in order to try to expose the brainwashing experiments going on there. He sacrificed himself in order to stall the Cleaners long enough for Lee and the others to escape before the lab went into lockdown.
He was saved by The Red Tazelwurm and reunited with the rest of the group in the school and aided them in trying to de-brainwash the school. Unfortunately he was soon overwhelmed by the rest of the student body whom managed to pin him down. Luckily Lee was able to snap them out of it and Holger was able to convince the others to destroy the phones. With all issues resolved Biffy finally asked Kimmie to the dance, to which she accepted.
After helping Lee sneak into her house, Kimmie stopped dating him due to him helping Lee spy on her mother, an event that creates some animosity between Lee and Biffy before they finally team up again to rescue the Tazelwurm. Biffy also designs a method to override Fort Nigma's various security measures including anti-cell phone jamming technology and a hidden camera to record the password.
Eventually, Kimmie forgives him, and begins dating him again. Sadly later on, during a date, another rift arises between the two decide to prank Greta Von Hoffman, Holger Holgaart, and Steve and ends up breaking their hearts. Biffy also attempts a rescue mission for Lee when he believes he's been captured by Finnwich by infiltrating his blimp, he wasn't but was still able to save Lee by taking control over his Steam-Mats.
After escaping from the crashing blimp Biffy teamed with Holger and Lee in a failed rescue mission for Finnwich and instead had to help Lee escape from The Serpent. On one occasion he teams with Lee and Holger again to take down the Serpent when he is trapped inside the school during a lice outbreak, failing to capture him.
Biffy also begins to suspect, and later confirms a cloning conspiracy involving the teachers of A Nigma. Biffy along with Cam, Holger and Lee form the band of heroes so that they can get to Coral Grove and rescue Tina and Jenny but as they were about to escape the prison, the security alarm causes a lockdown locking all of them inside.
However the gang comes into contact with Lynch Webber who was sent by Finnwich to get Lee, but the gang do not believe him and therefore they used him as distraction to get back on the submarine heading back to A Nigma High but Lynch manages to control the submarine into bringing them back to Coral Grove which caused the gang, especially Biffy to get angry Lynch for ruining a perfectly good escape at which they grabbed a pair of crystalizing guns and caused a mayhem at Coral Grove and teaming up with Holger to get Cassandra's robot suit and huge mega crystalizing gun to save Lee from Cassandra's army of hazmats by crystalizing all of them.
The gang reunites and went down to Finnwich's quarters where he attempts to kill both Lee and himself to which Biffy recognises as a double cross made by Finnwich himself and tries to blast him but were saved by the timely arrival of His Eminence who then imprisons most of the gang except Lee and Finnwich with force fields but was "saved" by Cassandra and her daughter Kimmie McAdams. After Cassandra crystallizes His Eminence, she reveals that she wanted to steal the technology inside the Pyramid in order to make another long series of fortunes to which Biffy asks Kimmie does she finally get his memo that her mom is evil to which Kimmie says totally, going to the point of saving Lee by crystalizing her mother.
Seeing that there was no more threats, the gang comes into a group hug to which Kimmie says to Biffy that underneath the stereotypical bully persona, he is secretly "such an affection hog".
While Biffy prefers to give off the appearance of a stereotypical bully, he does this mostly to preserve his reputation. In reality he can be a much kinder and helpful individual. He helps people when no one else is looking and appears to enjoy it, though he still takes the opportunity to mock them when he can. He claims he doesn't hate anybody, though he claims he only tolerates Lee. He's also said to have a short temper, claiming he would bully Lee for real if he caused the DOD to stay broken-up.
Biffy is to some extent reckless as shown when he aids Ping. He so far has pulled the fire alarm, led Lee to the girls wash-room, and even rushed Lee back to detention. Despite his reckless nature and bully ways he still does have some sense of caution as not even he would mess with the 15th graders.
Lee Ping - Lee and Biffy are acquaintances with Biffy usually bullying Ping. However after his days in detention he has grown to like Ping as a friend (though he refuses to admit it) and is willing to do reckless things for him. However, after Kimmie dumps Biffy because he teamed up with Lee to spy on her mum. He then told Lee he would not help him, and bullies Lee afterwards. Biffy eventually forgives him in "All That Taz".
Kimmie McAdams - the two are old friends but their relationship broke up in the 7th grade. However, they still seem to be on somewhat good terms because their relationship had improved after the events in "The Hair incident". During the school elections it is shown that while they still like each other their relationship has evolved into a type of rivalry and neither of them wants to let the other win. It is possible that Biffy met Kimmie through their parents, who both work at Mann, Wurst and Finnwich. This was later proven not to be true. Kimmie has since dumped Biffy because he teamed up with Lee to spy on her mother. She reconciled with him in "The Outcasts Strike Back!". They have a "date" in "Corndog Day Afternoon".
Camillio Martinez - Biffy seems prepetually angry at Cam as seen in "Clogspiracy", but that was due to him asking Kimmie out under hypnosis. They resolve their issues and work well together in "The Hydra".
In terms of physical prowess Biffy is stronger than most in the school, displayed when he carried a sofa to barricade some doors in School Hard and when he broke a large metal pipe in The Dance Part 2 he was even able to the detention room door closed while Barrage was tring to knock it down. He also seems to have good reflexes, as shown when he caught a water balloon that was launched at him (without it breaking) and is far taller than most students as well, even dwarfing the 15th graders and standing just below Barrage.
He is very proficient with computers and technology, although it should be noted that there are people better at decoding than him. He was unable to hack into Radcircles phone, while Irwin Dexter was able to solve the problem with relative ease (however Irwin could see the encryption with a computer whilst Biffy could not). He can also be considered to have above average intelligence, but once again he cannot be compared to very intelligent people like Ruby Kwee, who beat him at chess repeatedly.
Like Lee, Biffy cannot be hypnotised thanks to a genetic oddity.
- "[I'm] enjoying the cake, so what, this is how I like to eat it, LEAVE ME ALONE!"
- "Man, this is like a spy movie or something. Wait, doesn't that make me?-- "
- "Oh, and by the way, I hate you and your phone should be working right now."
- "Quick, don't let him get outside, oh great, HE'S GOT OUTSIDE."
- "Don't get all paranoid!.. Right now you sorta need all the friends you can get." - "The Down With Lee Club"
“Biffy would be "the Detentionaire", if he ever cared enough to sneak out. The detention room is kind of his base of operations, where he can spend his time maintaining his loner bad boy image and breaking into the school files. He's built like a fridge and feared by all, but if you spend enough time with him-like Lee has-you'll discover he has a soft side: a secret love for cats, zen meditation, and knitting. Biffy is Lee's co-pilot for sneaking out and getting back on time.”
- Biffy is stated to be vegetarian ('Revenge of the Cycle Killers').
- Biffy carries his cell phone under the right sleeve of his t-shirt. This is probably to reinforce his bad-boy image, since it gives the impression that it's a pack of cigarettes.
- Biffy is a fan of the band Dudes of Darkness, and will try hard not to get detention on any day they are playing for the school. Biffy even can't resist doing something if it means he will get DoD stuff for it.
- Biffy is said to weigh 300 pounds (although Lee probably made that up). 
- Lee calls Biffy his "prison cell mate".
- The "kitty" on Biffy's shirt apparently has a name but he never said what it was.
- Although it is likely Mrs. Rumplekittykat.
- Whenever Biffy is strategizing he uses his signature "evil genius finger taps".
- Biffy's parents both work at Mobile Wireless Federation. When they grounded him they had him go to the building after school where he was made to get coffee for his parents and the other employees (such as Gary).
- Biffy's favourite dessert are cakes.
- As of "Common Denominator" even the 15th Graders, the biggest bullies at the school, are a little afraid of Biffy.
- Biffy can not be hypnotized, and is one of the few characters to be immune to the Prank Song.
- According to "The Hydra", Biffy named his left biceps "Meltdown" and his left "Pummel".
- Detentionaire Series 1, Episode 13 - "The Hair Incident"
- Detentionaire Series: Season 1, episode 6 - "Dudes of Darkness"
- Detentionaire TV series: Season 1, episode 3 - "Skate or Die"
- Detentionaire TV series: Season 1, episode 7 - "28 Sneezes Later"
- Detentionaire TV series: Season 1, episode 8 - "Disco History Times"
- Detentionaire TV series: Season 1, episode 13 - "The Hair Incident"
- Detentionaire Series 2, Episode 1 - "The Cam-didate"
- Detentionaire Series 1, Episode 01 - "Blitzkrieg Bop'd"
- Detentionaire Extra - Lee Introduces Biffy
- Detentionaire Series 2, Episode 4 - "Double Date"