Deadly Dogs!
Platform: Intellivision
Region: USA
Media: Cartridge
Controller: INTV
Genre: Action 
Gametype: Hack
Release Year: 1987
Developer: None
Publisher: None
Players: 1
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While debugging the cross assembler and disassembler he had written to develop the new INTV games, Dave Warhol tested the software on one of his favorite Mattel Electronics game, TRON Deadly Discs. He substituted the men in the game with the hot dogs from the BurgerTime cartridge, creating a new game: Deadly Dogs! Later, while preparing Dig Dug for release, Dave found there was enough space on the cartridge to slip in his new game. To play it: Press 47 (four and seven simultaneously) on both hand controllers and press reset.

http://www.intellivisiongames.com/bluesky/games/credits/intv3.html#digdug