According to legal docs filed Monday, Pras hired Marshall Tyler back in 2009 to direct a documentary film called "Paper Dreams"-- about the rapper's real-life, death-defying incident with pirates off the East African coast.

In the suit, Pras claims he was "taken captive" by Somali pirates sometime in 2009 -- however multiple reports say Pras, and his film crew, merely witnessed the famous capture of the Maersk Alabama in April 2009.

According to his lawsuit, Pras says he put up $70k of his own money to cover filming and travel expenses --but says after the footage was shot, Marshall failed to hand it over.

Pras claims he's repeatedly asked for the goods, but never heard a word back. Now he's suing to get the footage ... or at least recover his 70 grand, plus damages.

A rep for Marshall says, "Pras is trying to assert ownership on material that Marshall owns the copyright to."