Captain Morgan Sues -- Shiver Me Timbers ... My Look-Alike's Selling Drugs!!!

Captain Morgan is putting his foot down -- not on a barrel of rum ... on another Captain it claims is ruining its business by using a similar character to sell psychedelic drugs.

The company that's drawn the Captain's ire is Captain Amsterdam. According to the lawsuit, Captain Amsterdam sells e-cigarette refills, as well as "psychedelic and stimulant drugs such as salvia" ... a throwback to Miley's escapades with salvia.

Morgan claims Amsterdam sells a whole line of "questionable" goods using various Captain names, including Captain E-Juice, Captain Salvia and Captain Kava.