Timmy Triangle is an alter-ego of Timmy that was in One Man Banned.
After Timmy Turner failed at band tryouts led by Mr. Bickles (he caused the entire auditorium to collapse with his poor playing), Timmy wished his triangle music would be loved by everyone who heard it. As a result of this wish, he becomes a musical superstar with a number of hit records and finally the only one with hit records. His personality changes, as well. He, also, makes very foolish wishes (even for Timmy) such as wishing that the entire planet Earth was a stadium, known as the Timmydome.
He looks like a later version of Elvis Presley (the so-called fat Elvis) and speaks like him. He, also, begins speaking in the third person using phrases like "Timmy's still the same ooollllllldddd Timmy" and dresses up like Michael Jackson in "Thriller".
As Timmy began to top the charts, he slowly began to display signs of decadence, wishing for a huge mansion that blocks the sun, and a stadium that takes up the entire Earth. Finally, he gets so arrogant, he decides that he neither needs his parents OR his godfamily, so Cosmo and Wanda leave and take their magic. Without magic, Timmy reverts to his poor playing. After apologizing to his fairies and his parents, Timmy is somewhat back to normal. However, he goes through a final stage in which he has an "ill advised comeback" nearly destroying Earth with his poor music. This effectively meant the end of Timmy Triangle.