The Adventures of Mac and Bloo is a fan-made crossover series that follows Mac and Bloo (and later Wilt, Eduardo, and Coco) from Foster's Home for Imaginary Friends as they go on a magical adventure, meeting new friends, exploring new places, and battling fiendish villains. Including Mac's bully for a brother Terrence, and the evil fairy Maleficent.
The violin music from the opening theme of the How the Grinch Stole Christmas TV special plays when the scene from the Foster's pilot movie "House of Bloo's" where Bloo jumps around and lands on Mac is shown and quickly morphs into the image of Bloo on Mac with the words "Never Forgotten" as "MacandBloo4ever Pictures" in blue letters appears (this being the MacandBloo4ever Pictures trademark logo). The song "Best of Friends" from The Fox and the Hound plays as the following scenes from various Foster's episodes appear on screen to go with certain parts of the song: Mac and Bloo arrive at Foster's for the first time (House of Bloo's), Bloo jumps around and lands on Mac (House of Bloo's), Mac and Bloo play on the seesaw (Berry Scary), Mac and Bloo toss pizza dough in the air (Berry Scary), Mac and Bloo talk to each other about how they're best friends (Berry Scary), Mac and Bloo playing in the mud (Bloooo), Mac talks about Bloo during show-and-tell (Bloo's Brothers), Mac and Bloo laugh their heads off after Jokey tells them an extremely funny joke (Adoptcalypse Now), Mac follows his mom into his bedroom (House of Bloo's), Mac's mother talks to him about how she thinks that he's too old for Bloo (House of Bloo's), Bloo listens through the door to Mac and his mom talking (House of Bloo's), Mac sadly lowers his head while in bed (House of Bloo's), Mac talks to Bloo as they walk through the front yard of Foster's during the Foster's 5 Year Creator Reunion Picnic Weekend (Good Wilt Hunting), Bloo hugs Mac after Berry is gone forever (Affair Weather Friends), Bloo telling Mac that taking him to Foster's was a perfect idea all along (House of Bloo's), Mac looking out the window on a rainy night (The Sweet Stench of Success), a slow motion flashback of Bloo jumping on Mac (The Sweet Stench of Success), Mac and Bloo running alongside each other as they race for the toy chest (Destination Imagination) with "The Adventures of Mac and Bloo" in blue letters appearing on screen. The scene where Mac and Bloo race alongside each other as they race for the toy chest repeats itself until the song ends and it fades to black.