Dock Ellis was a pitcher in the 60s and 70s who is best known for his years with the Pittsburgh Pirates (1968-75). He played for four other teams (including the Yankees in 76-77) before finishing with the Pirates in 1979. He appeared in the 1971 All-Star game and won a title with the Pirates that same year.
Dock Ellis was also one of the most "colorful" players in the modern era. He hit Reggie Jackson in the face with a pitch in retaliation for a homer Jackson hit off Ellis in the 1971 All-Star game. In one game in 1974 he attempted to hit every batter in the Cincinnati lineup and was pulled in the first inning after hitting three guys in a row and throwing two pitches at Johnny Bench's head. Ellis was also a heavy user of "recreational" drugs, including LSD, and that is what brings us to this particular story.
In 1970, Dock Ellis threw the first no-hitter of the season in a game against the Padres in San Diego. What came out years later was that Dock Ellis was high on LSD when he pitched. That story came from Dock Ellis himself. He apparently had issues with seeing the ball and the batters. But don't take it from me. Here is James Blagden animating the story told by Dock Ellis himself. Enjoy.
For the record, after baseball Ellis went on to do many admirable things. Among these was becomig an anti-drug counselor in Los Angeles and starting the Black Athletes Foundation for Sickle Cell Research. Ellis passed away in 2008 at the age of 63.