Unreleased Off Your Rocker Prototype
Amiga originally had plans to release both games and their own sort of Supercharger called the Power Module for the Atari 2600. The Power Module would not only allow for larger / better games, but would also add a 3D ability to the 2600 (albeit only if you wore those generic red / blue glasses). Unfortunately as was the case with many companies at the time, these aspirations didn't come to pass.
Amiga only released one game before abandoning the then crumbling 2600 market for pastures new. However before leaving the Atari 2600 market, Amiga had sent its second game "Off Your Rocker" off to another company to have labels applied. Unfortunately since Amiga had pulled the plug on its 2600 division they just didn't have the money to pay for these labels and so the carts were kept by the label company. Years later this same company sold off all these cartridges as scrap to a company called Pleasant Valley Video. They quickly put their very own homemade labels on them (so they were easier to flip / sell on at a profit) and sold them index to the 2600 community.