Jack creates a poisonous gaseous compound, ammonium dysterate (pronounced 'disstuhrate'), from household chemicals. It is completely fictional: there is no such compound. The TV and DVD subtitles incorrectly render the name as 'ammonium distearate' (pronounced 'die-stee-ahrate'). This does exist and could conceivably (but not easily) be made from materials such as ammonia-based cleaners and soaps/detergents but it would be neither poisonous not gaseous.