Chompey is a shark that Dan and Chris stole from the "City of Industry Aquarium" in "Dan Vs. The Beach".
Chris was forced by Dan to tranquilize him, however it failed making Chompey chase Chris, who accidentally tranquilized Dan. The duo managed to tie Chompey to the top of Chris' car driving to the beach. After getting in Dan's boat, the trio set sail where Chompey (tied to the front of the boat) kept trying to bite his capers. Dan thought this was cute, thus calling him Chompey or Greg (after a few more bites Dan decided Chompey). They pushed him off the boat, and after a few seconds he pushed Chris and Dan onto a deserted island.