Mac's 5-year-old imaginary friend and best friend who resembles a simple, domed cylinder. Bloo is sometimes self-centered, egotistic and narcissistic almost to the point of psychotic delusion and has a knack for getting into trouble. However, he still has a good 심장 and apologizes for his actions. Bloo loves paddleballs even though he can't make the ball hit the paddle (though the only time he was able to do it was in the episode "Let Your 토끼 Down"). His full name is "Blooregard Q. Kazoo". He became increasingly mischievous over the run over the series and is shown to have bad memory some of the time. He is voiced 의해 Keith Ferguson.

We all 사랑 Bloo. He is the life of the show, the 젤리 on the 땅콩 버터 sandwhich, the sprinkles on the cupcake. Without him Foster's 집 for Imaginary 프렌즈 would be nothing.