Warner Bros. Sued by Company Claiming 'Westworld' App Game is a Rip-Off

Warner Bros. got in bed with a tech company that jacked codes in order to fast-track and produce its "Westworld" mobile app ... so claims another company in a new lawsuit.

The gaming company, Bethesda Softworks, is suing the media giant and Behaviour Interactive and, in the suit, says Behaviour stole its designs, artwork and codes ... and used them in the "Westworld" game.

In docs, obtained by TMZ, Bethesda says it hired Behaviour first, in 2014, to work on its popular mobile app game, "Fallout Shelter." Later, after "Westworld" premiered in 2016 ... Behaviour went on to create the "Westworld" game for Warner Bros.

Bethesda's issue, according to the suit, is that Behaviour used its "Fallout Shelter" coding for the "Westworld" game. And, Bethesda believes there's a smoking gun -- the same bugs that appeared in an earlier version of 'Fallout' also showed up in the "Westworld" game.