[TOMT] [MOVIE] [HORROR] The lost and never found thriller/horror movie from my childhood

There were two friends preparing a school report and one of them was dressed in some kind of kite or vulture football team mascot costume, I remember for sure that they had a fountain installed in the butt area and green liquid was shooting out of it right at the class bully to demonstrate kite (?) defecation. At the end of the movie it turned out that the guy in the costume was a murderer all the time and during his death at the hands of the main character he was stating one of the facts from life about birds that they shared during the science project – probably some edgyish cornball about kites being a lonesome birds or idk