Both accounts are courtesy of excerpts taken from Redleg Journal:
June 16, 1978 - Tom Seaver pitches the only no-hitter of his career in a 4-0 Reds win over St. Louis at Riverfront Stadium. Previously, Seaver had entered the ninth inning with a no-hitter three times, and surrendered a base hit on each occasion. In this game in the ninth, he walked Jerry Mumphrey leading off, induced Lou Brock to fly out to left field, retired Gerry Templeton on a force out, and ended the game on a weak grounder by George Hendrick to Dan Driessen at first base. Seaver walked three and struck out three.
Seaver was the third native of Fresno, California to pitch a no-hitter for the Reds. The first two were Ewell Blackwell and Jim Maloney.
Seaver is also the last pitcher in club history to throw a true no-hitter in a game. Tom Browning threw the franchise's first and only perfect game over two years later on September 16, 1988. No Reds pitcher has thrown a no-hitter since.
June 16, 1984 - Mario Soto blows his cool for the second time in three weeks. Playing the Braves in Atlanta, Soto sailed three pitches at the noggin of Claudell Washington in the third inning in retaliation for Washington's lead-off homer in the first. In the fifth, Washington swung and missed at Soto's first pitch, and the bat flew out of his hands, landing near the pitcher's mound. Fearing mayhem, home plate umpire Lanny Harris followed Washington as the hitter retrieved the bat. Washington turned on Harris and threw the ump to the ground. Dann Bilardello and Atlanta third base coach Joe Pignatano leaped in as peacemakers, and Soto fired the ball into the tangle of bodies with the intent of hitting Washington, but struck Harris and Pignatano instead. After Soto and Washington were ejected, the Reds won, 2-1.
Soto drew a five-day suspension and a $5,000 fine for his actions.
After doing a little research about the incident myself, I dug up this 1984 article from Sports Illustrated's vault. It goes into greater detail about the fiasco, as well as events leading up to it and the reasoning behind Soto's occasional flare-ups.