PvP is one of the longest running webcomics in existence, and it is still being up regularly.  At one point, it was even adding new comics every day, though I'm not sure if this is still the case.

Anyway, as one could imagine, adding new comics every day can be pretty taxing, so one week PvP did a callout to other artists to help fill in the void while the creator took some time off.  Seeing as PvP was one of the more popular comics, I jumped at the chance to get my work seen by a much larger audience.  However, there was a problem - I never read PvP, and knew next to nothing of their characters.

 

So, after some brief reading, I created this strip and submitted it.  In an effort to increase my chance of being selected, I even shaded the comic, which I rarely did for my own strip (" Look!  He figured out the 'airbrush tool'! ")

 

Alas, it was all for naught, as my comic was never selected.  It's not surprising as I look at this strip now - the joke is not really all that good.  Nevertheless, at the time, it was mildly dissapointing.