Mac is the main protagonist of Foster's Home for Imaginary Friends. He is an 8-year-old boy who is the creator of Bloo. Mac's voice was high early in the series, but as the show went on, his voice noticeably became slightly deeper.
- "Mac is a smart, creative, somewhat shy boy. He spends most of his time hanging out with Bloo and his new friends at Foster's, where he can stay safely away from his obnoxious bully of a brother, Terrence."
Mac has long brown hair and fair skin. He wears a red t-shirt with a white sweater underneath, black and white tennis shoes, a dark green backpack, and tan khaki pants.
When he goes to bed, he wears blue pajamas, with a button-up top.
Mac's winter outfit consists of a red hoodie and a red beanie with white trimming on the front.
Mac's outfit when it's raining outside consists of a red raincoat with his hoodie up.
Mac is a bright, selfless, smart, sensible, imaginative young boy, and the creator of Bloo. He created Bloo when he was three years old. According to a trading card in the Foster's Home For Imaginary Friends Leapster game, he created Bloo after he had to give away his favorite blanket. Mac is unusually clever, and almost always knows what to do when there is a problem. He has a keen sense of reason and tends to be the one to settle any mishaps that the imaginary friends (particularly Bloo) end up causing. Mac is usually very good-natured, despite Bloo's continuing antics. No matter what happens to Bloo, or any other member of the house, Mac is usually the one to bail them out. However, he has been known to snap; Mac has a strong moral personality and he always avoids doing wrong things but is sometimes pushed to do otherwise, almost always by Bloo. That said, he can be very rambunctious and childish when he wants to be, and generally has no problem pulling pranks or messing around with Bloo, as long as nobody gets hurt. Some episodes also have him being more naïve and childlike than usual, like "Adoptcalypse Now" or "Fools and Regulations".
Mac's personality goes from very sensible, to a complete lunatic, if he eats even the smallest amount of sugar, which is the main reason why his mother won't let him have any. One example of this is in "Partying Is Such Sweet Soiree", in which one drop of heavily-sugared punch causes Mac to go completely crazy. He disrupted Bloo's wild party by eating sweets and embarked on a quest for more sugar, which included him streaking through town in the middle of the night. He also became "sugar high" in the episode "Affair Weather Friends", in which he got so mad at Bloo that he decided to eat numerous ice cream sundaes. In the Halloween special episode "Nightmare on Wilson Way", everyone, including Mac himself, was very serious about keeping Mac tied to a bed in order to keep him from eating candy. Later, Bloo, thinking everyone except himself and Mac were turned into zombies, escaped the room and obtained some Halloween candy, and since Mac was trapped on a bed and couldn't move, he couldn't stop Bloo from putting the candy in his mouth and he ended up dashing through the house and eventually running in his underwear as he took candy from trick-or-treaters. He also has a sugar rush in "Race for Your Life Mac & Bloo", after drinking an energy drink, but only ends up running around crazy, and not becoming obsessed with finding more sugar. Despite his condition, Mac and Bloo are seen stopping for ice cream on their way to bring Duchess back to Foster's in "Duchess of Wails". Mac is also seen drinking root beer at the end of "Schlock Star", eating candy in "Squeeze the Day" and "I Only Have Surprise for You" and cookies in "World Wide Wabbit", "The Bloo Superdude and the Magic Potato of Power" and is about to eat cookies in "Go Goo Go." Even though he ate sugar-free cookies in the series finale "Goodbye to Bloo", it is never stated whether the cookies he was eating in "World Wide Wabbit", "The Bloo Superdude and the Magic Potato of Power" and the cookies he was about to eat in "Go Goo Go" were sugar-free. For the first time Mac's sugar addiction was shown, when Bloo attempted to calm him down using sugar-free gum, Mac exclaimed "IT BURNS US!", in a manner similar to the character of Gollum from The Hobbit and The Lord of the Rings.
Another thing to note about Mac's sugar addiction is that, in his crazed state, Mac experiences a significant increase in speed, strength, and combat skills. This is shown in "Partying Is Such Sweet Soiree" when he ran out of Foster's in mere seconds, and in "Nightmare on Wilson Way", when he rushed through everyone in the whole house, subdued Wilt and Coco in one punch, and smashed Eduardo through the front door, before lifting him above his head and tossing him away.
Out of all of Mac's known sugar rushes, he has eaten large amounts of sugar but has shown no signs of gaining weight or getting sick, likely due to his massively increased metabolism while undergoing one.
Mac's sugar rush is his and Bloo's synergy attack in Cartoon Network Punch Time Explosion XL. When they grab an assist pickup and summon their synergy partner, Peppermint Larry from The Marvelous Misadventures of Flapjack, he appears with a barrel full of candy. Mac dives in and eats a large amount in seconds. After becoming hyperactive from eating sugar, Mac zips around the stage sending any opponents in his path flying, with Bloo clinging to his back.
Mac has a close connection with Madame Foster, with whom he shares a close kinship, particularly in that neither of them is willing to give up their imaginary friend, where most children would have done so long ago, in Madame Foster's case. Mac also seems to get along decently well with Mr. Herriman, despite the fact he has such a great dislike of Bloo.
Mac has great affection for the house's caregiver Frankie, to the point of harboring an intense crush on her, which is shown in five episodes: in "Frankie My Dear", where he, Bloo, Prince Charming and Chris the pizza guy compete for her love (and where he first develops his crush on Frankie.), in "Ticket to Rod", where he has an opportunity to go out with Frankie on the premiere of the new Rod Tango movie (and ultimately ends up staying at the house to help her with chores when she can't go), in "Race For Your Life Mac & Bloo", where he imagines being kissed by Frankie in his race victory daydream (and then makes her cry in a second daydream where everyone finds out he cheated to win), in "Bad Dare Day", where he is dared to tell Frankie that he loves her (and, at the end, Bloo says that he posted Mac's crush on the Foster's blog, much to Mac's displeasure), and in "Goodbye to Bloo", where Frankie wants to see him alone and says she wants to say something to him, Mac thinks she's going to say she loves him, then she says she has something to give him and he thinks Frankie is going to kiss him (he even closes his eyes and puckers up his lips). Aside from his crush, Mac is a loyal and helpful friend to Frankie and vice versa. She is also one of the few human friends he has and is usually the only one he sees on a daily basis, with Goo only appearing from time to time.
Most of these were given to Mac by Bloo.
Mac-Attack, My Butler Wimpy, Wimpy, Mr. Smarty Pants, Mr. Destructo, Rex Carsalot, Kid, Madame Lad, Man, Honey, Sweetie, Hon, Son, Sir Mac, Blockhead, El Stupido, Ditchy McAbandonpants, Daddy, Sonny Jim, My Son, Señor Mac, My Naked Friend, Everyone's Favorite 8-year-old, Ol' Nudie, Guy With Tickets, The Comeback Kid, Maco the Clown, My Primitive Uncultured Neanderthal Companion, Sleepyhead, Tree Hugger, Mr. Librarian, Bloo, Buddy, Pal, The Little Boy, Boy, My Boy, Blinky, Master Mac, Smarty Pants, Grandmaster Mac, My Child, The Guy We All Know and Love, Steven, The One You Know and Love, Weirdo, Diamond Thief Suspect, The Little Boy Without a Father, Kiddo, Sidekick, Forgeter, My Old Chum, Mr. I Don't Care About Other People's Feelings, Homey, Half-pint, Young Fella, My Great Great Great Grandson, Insolent Youth, The Awesome Creator of Everything, The Ultimate Creator of Everything, The Great Creator of Everything, Sir, Mac Old Bean, Old Buddy, Dear, Darling, Sweetheart, Angel Face, Schnookums, Baby Cakes, Mister, My Lunatic Friend, My Guy, The Candy Monster, Mr. Poops on Everything, Maco, Turkey, Young Man, Sonny, Clumsy, Bucko, Spoil Sport, Shaggy Brown, My Associate
Away from Foster's, Mac lives in an apartment with his mother and his older brother. Terrence is the stereotypical cruel older brother, who gets great joy out of making Mac's life miserable. In fact, Terrence is partially the reason that Mac created Bloo. There is virtually no brotherly love between Mac and Terrence, and Mac takes great joy in what punishments come his lowlife brother's way. Mac's mother is a working mother, who, at the start of the series, comes to the opinion that Mac is too old for an imaginary friend, and requests that Mac gets rid of Bloo, leading to Bloo moving to Foster's. Mac's mother is mostly mentioned in the series, and her face has never been shown; she is often shown from behind, with her head cut out of frame while facing the screen, or with objects blocking her face from views, like Wizard Kelly from the Proud Family and Mrs. Bellum from The Powerpuff Girls. Mac also reveals to have a female cousin named Candy in "The Bride to Beat". She is an adult and is getting married. Mac also seems to have a grandma, as he mentions his grandma in "Ticket to Rod."
Throughout the series, Mac's voice actor has been Sean Marquette, who, surprisingly, wasn't replaced after he went through puberty. Rather, his voice was digitally mastered to a higher pitch by using sound audio to still sound like Mac from before, even though it is obvious when one compares Mac's early season 1 voice to his voice in later episodes and then on. This is just like Gerald's voice on Hey Arnold!, Hey Arnold!: The Movie, and Hey Arnold!: The Jungle Movie, and Skippy's voice on Animaniacs and in Wakko's Wish.
He and Bloo are some of the first people to encounter a Fusion. After Terrafuser lands in Foster's Home, he and Bloo stepped outside to investigate. Fusion Spawns emerge from the space rock and heads towards the house. Mac suggests that they are new Imaginary friends. After Bloo confronts the Fusion Spawns and tells them to leave, the Fusion Spawns begin to overrun them in a huge swarm. Dexter soon arrives with Ben (Four Arms) to protect Foster's Home. After defeating the Fusion Spawn, Bloo begins to gloat, claiming it was him who saved the day. Mac shrugs him off, and then thanks Dexter for saving them. The group soon heads to Sector V to help Numbuhs Five and Two, Blossom and Bubbles defend Sector V.
After a Quicksave they head back to Dexlabs to discuss the situation. After Dexter and Prof. Utonium proposes a plan to defeat the threat, he incorporates a plan to blast the main terrafuser with his new Electro Pulse Cannon, while a group of people attacks the other two terrafuser. He requests that the heroes must team up to complete the mission. With everyone unsure about the idea, Bloo decides that he won't help completely, making Mac force him to stay and convincing the other heroes to corporate. Dexter soon reveals that the two most important parts for his EPC to work were in Mandark Industries and at Mojo's Volcano. Dexter and Utonium propose that there be one team would steal one of the parts, and the other team would steal the other part. Mac joined Numbuh Five, Dee Dee, and Bloo to steal the part from Mandark Industries. After fighting their way through a wave of Mandroids, winging across a lake of alligators, and sliding down a pipe hole they encountered Mandark. They told Mandark the part was, and Dee Dee convinced him to corporate with only one condition; that he could come along with them.
The two teams regroup onboard Dexter's helicarrier, but Dexter refuses to work with Mandark and wants to kick him off the helicarrier. Dee Dee rejects the idea and instead convinces the two to work together. The helicarrier is soon attacked by flying Fusion spawns. Mac and the others hold off the Fusion monsters while Dexter finishes with the EPC. Unfortunately, Mandark is distracted by his infatuation with Dee Dee causing him to make a fatal error in programming the EPC which jams it at a crucial moment. Dexter is able to fix the error, and fires the cannon at the main terrafuser, but not before it shoots a signal that brought Planet Fusion to Earth.
• In 2021, Mac would be 25 years old.
- Mac's voice actor is Sean Marquette in the series, but in Cartoon Network: Punch Time Explosion and the updated XL version, he is voiced by Grey DeLisle (who, coincidentally, voiced Frankie), making him sound the way he sounded in Season 1. He and Bloo are one of the few pair fighters (and the only playable characters from Foster's) in the game.
- Only Mac's mom is shown in the series - his dad is never seen or mentioned. Since Mac and Terrence's dad clearly isn't around, Mac's mom appears to be raising him and his brother as a single parent.
- As shown in "The Sweet Stench of Success", Mac knows morse code. This was also shown in Read 'Em and Weep.
- Mac appears in every episode except "Pranks for Nothing", and is absent in 7 shorts: All Zapped Up, Bad to the Phone, Give Pizza a Chance, Fistful of Cereal, Drawing Bored, Coconuts, and Birthday Cake Bloos.
- Mac's golden trading card statistics in the "Foster's Home for Imaginary Friends" Leapster game include:
- He Is GREAT at paddle-ball.
- Has never eaten at Foster's Frijoles.
- He is 4 feet, 3 inches tall.
- He created Bloo after he had to give away his favorite blanket.
- Mac briefly appeared with Bloo in the Powerpuff Girls episode "The Powerpuff Girls Rule".
- Mac is mentioned in the Steven Universe episode "Say Uncle" by Uncle Grandpa.
- Mac also appears in the Uncle Grandpa episode "Pizza Eve" where he's seen clapping in the audience and sitting beside Mordecai and Rigby from Regular Show.
- Series creator Craig McCracken said in an interview that Mac was based on his childhood at the age of seven following his father's passing.
- He has a dog, as seen in I Only Have Surprise for You
- When Mac eats even a single crystal of sugar, he goes all over the place, similar to Wanda from The Fairly Oddparents with chocolate.
- A cardboard cutout of Mac appeared in The Grim Adventures of Billy and Mandy, in episode ''Billy and Mandy Moon the Moon'', along with a cardboard cutout of Bloo.
- Mac shares many similar characteristics to Tommy from Robotboy, another Cartoon Network show:
- They have similar hair styles and head shapes.
- Both have a unique friend (Mac has his imaginary friend, Bloo. Tommy has his robot friend, Robotboy).
- Both have strained relationships with their older brothers due to bullying.
- Assuming Bloo has the same last name as Mac (His full name being Blooregard Q. Kazoo"), it is possible that Mac's last name is also "Kazoo."
- Mac made a cameo in the Codename: Kids Next Door and The Grim Adventures of Billy and Mandy crossover episode, "The Grim Adventures of the Kids Next Door". He along with Goo were two of the kids to pop out of the recently defeated Delightful Reaper, after Grim and Numbuh 1 destroyed it and saved the world from it. This reveals he and Goo gotten assimilated into it, and could prove that many of the locations each Cartoon Network show takes place in including Foster's Home for Imaginary Friends, seem to all be in the exact same world, which could prove each of the Cartoon Network shows are connected together.
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