B is a flash cartoon made by the famous StrawberryClock. It is generally considered as the driving force behind the Clock Crew due to its "miraculous" survival in the Flash Portal despite being nothing more than a single letter B with no animation- which is against Tom Fulp's specifications for a flash submission. The movie has since maintained a higher score through support from CC.
The infamous cartoon containing only a red B
It was submitted to Newgrounds on August 15, 2001 by Newgrounds user StrawberryClock (AKA Coolboyman). The flash is simply one frame with a red letter "B" in the center of the screen. It passed with an initially low score, and won Turd of the Week.
Other people who founded the Clock Crew around the character Strawberry Clock looked upon B as the Clock Crew's central pillar, and the day of its submission is celebrated as Clock Day, a very large event on Newgrounds.