Mac is a bright, unselfish, creative and somewhat shy boy who created Blooregard Q. Kazoo when he was three years old. Mac is unusually clever and almost always knows what to do when there is a problem. He stands three feet, six inches tall and weighing 67 pounds (according to his Coco Card) with a sense of reason and somewhat large vocabulary to match. He 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 strongly moral personality and he always avoids doing wrong things, but sometimes he is 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. Foster's creator Craig McCracken said in an interview that Mac was based on his childhood at the age of seven following his father's passing. Mac's personality goes from very sensible to lunatic if he gets 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 when one drop of heavily-sugared punch causes Mac to go completely crazy. He disrupted Bloo's secret party by eating all the sweets and embarked on a quest for more sugar, which included him streaking through town in the middle of the night. Mac is also enemies with Frankie.