I actually have video of this...Trying to upload it to YouTube.com now. This has happened to me a couple of times. Once on the back of Padres and once on Rumrunners. It's probably the most beneficial glitch ever. Moreso than the undead skeleton and the ability to have no grogginess and full ammo all the time.
Here's a screen shot of my LV14 character killing a LV19 giant crab on Rumrunners.