I'D SAY HE'S HOT ON OUR TAIL
I'D SAY HE'S HOT ON OUR TAIL (also known as Adventures of Super Mario Bros. 3 Remixed) is officially recognised as being the first YouTube Poop ever made by SuperYoshi on December 22, 2004. It has been remastered by mrSimon using a better quality picture source. It is so named by a quote said by Luigi, repeated several times for emphasis.
After installing Windows XP, SuperYoshi had noticed the program "Windows Movie Maker". He proceeded to test it by using an Adventures of Super Mario Bros. 3 episode, Recycled Koopa to be specific. Upon messing around with it a bit, adding annoying bits of repetition and the like, he uploaded it to Sheezyart. It was received well, and SuperYoshi proceeded to upload more of those videos, creating the mess we know as YouTube Poop.
The original Sheezyart ending is markedly different from the Youtube ending, as pointed out by SuperYoshi on twitter during the video's (and to that effect all of Youtube Poop's) 15th anniversary. The repeating clip of King Koopa's doomship crashing into his castle is extended even longer, with onscreen text poking fun at the repetition of the segment, while on Youtube the repeating sequence is cut short by a final reprise of "A KOOPA TAIL!"
Despite being the first YouTube Poop created, it was actually uploaded to YouTube a few years later, November 27, 2006 to be precise. The video that holds the distinction of "first poop to be available on YouTube" is "Sonic and Robotnik's Sodomy Hour!", uploaded on April 1, 2006.