Manning has worked out with his receivers at Duke University and decided to play a little prank on Eric Decker. As you can see from the photo above, provided by Bleacher Report, Manning sends Decker a fake invoice from Duke, for his training services.
Manning going all the way back to his Tennessee days, is known as a legendary prankster (look it up, he got in trouble for mooning a female trainer).
Unfortunately, Twitter alerted Decker to the prank, but it was fun while it lasted.