About

Pacific University in Oregon conducted an experiment in which a shrimp injected with pathogenic bacteria was placed on an underwater treadmill upon which this shrimp walked/swam for food.
The experiment was to examine if bacterial infection could change anaerobic pathways, and conducted by two professors: Dr. David Scholnick of Pacific University, and Dr. Louis Burnett of the College of Charleston.
The original video of the shrimp was posted on the webpage of Professor Scholnick, which you can find here.
"I guess people find the prospect of watching a shrimp exercise on a treadmill amazing," Scholnick later said of the video, as stated in this article.

The video was picked up by Youtube user duffman452001 and set to the tune of Yakety Sax, and has so far gotten over one million views. In the video notes, Duffman said he just took two things that made him laugh and combined them into one of the funniest things he's ever seen:

Derivatives

Many variations followed after.

The Final Countdown

Chariots of Fire/Gonna Fly Now

Right Thurr

SexyBack

Eye of the Tiger

Shrimp Running to William Tell

Physical Music

Heart's on Fire

Curtis Mayfield

DUB ЯEMIX

Chacarron Macarron

Run to the Hills

Daft Shrimp

Crevette sur un Tapis Roulant

ytmnd

Not long after, YTMNDs came around with it. The first of which, was Shrimp running on tiny aquatic treadmill(?!) by shilrobot on October 10, 2006.

MORE:

• Eye of the Tiger Shrimp
• OK Go Shrimp
• Snakes on a Plane version

Links

Late in 2008, Urlesque wrote an article on it: The 6 Craziest Alternate Soundtracks to the Shrimp on a Treadmill Video. For a timeline of a number of the shrimp on a treadmill videos, see this Dipity timeline.

- MSNBC article regarding the experiment
- Buzzfeed
- Telegraph article
- Huffington Post