Just about every 2600 game released by Atari between 1982 and 1984, the "silver label era," was either an arcade port, a movie tie-in, or part of a series, like the RealSports and Sesame Street games. One of the few exceptions was Taz. An original game starring the character from Looney Toons, Taz features the Tasmanian Devil doing what he does best: eating!
Taz is a historic game in the Atari 2600's library, for two reasons. One, this was the first game published by Atari to credit the programmer on the box. Years after Activision and other companies started turning their developers into celebrities, Atari was finally persuaded by an ultimatum from Taz programmer Steve Woita: give credit or find another programmer. Taz also made the history books for how it was sold to European gamers. Nowadays if a publisher figures a game won't sell very well in a particular market, they simply don't release the game in that market. For Taz, Atari decided European gamers not familiar with the Tasmanian Devil would instead prefer a game featuring Asterix and Obelix, a pair of French comic strip characters best known for their repeated run-ins with the Roman army of old. So, Taz became Asterix, a game where European players can try their luck helping Asterix and Obelix clean up after a Roman battle.
Ultimately, neither Taz nor Asterix sold many cartridges, and both are now among the rarer games to collect for the Atari 2600. Finding both cartridges at the same time is particularly difficult, since Taz was only sold in the Americas, and Asterix was sold primarily in Europe, with perhaps a few cartridges also available in Canada. Really though, once you find one game, you have them both.