An Eephus pitch, (also spelled Ephus) in baseball, is considered a "junk" pitch with very low speed. The delivery from the pitcher has very low velocity and usually catches the hitter off-guard. Its invention is attributed to Rip Sewell of the Pittsburgh Pirates in the 1930s. According to manager Frankie Frisch, the pitch was named by outfielder Maurice Van Robays. When asked what it meant, van Robays replied “Eephus ain’t nothin’.” But when Sewell asked why he named it that he said "Eephus means nothin' and so does the pitch"
The Eephus pitch is thrown overhand like most pitches, but is characterized by an unusual high arcing trajectory and corresponding slow velocity, bearing more resemblance to a slow-pitch softball delivery than to a traditional baseball pitch. It is considered a trick pitch because, in comparison to normal baseball pitches (which run from 70 to 100 miles per hour), an Eephus pitch appears to move in slow motion.
After appearing in over 300 major league games, Rip Sewell only gave up one career home run off the Eephus, to Ted Williams in the 1946 All-Star Game. Williams challenged Sewell to throw the Eephus. Sewell obliged, and Williams missed the pitch. However, Sewell then announced that he was going to throw the pitch again, and Williams clobbered it for a home run. Years later, however, Williams admitted that he had been running towards the pitcher’s mound as he hit the ball, and photographs reveal that he was in fact a few feet in front of the batter’s box when he made contact. Since under Rule 6.06(a) of the Official Baseball Rules a batter is out for illegal action when he hits a ball with one or both feet on the ground entirely outside the batter’s box, Williams would have been out had it been spotted by an umpire.
Pitchers known to have employed the Eephus pitch include: Dave LaRoche (whose pitch was known as LaLob), Bob Tewksbury, Kazuhito Tadano , and Orlando Hernandez. Left-hander Bill Lee, known as “The Space Man,” threw a variant of it he called the Space Ball, or, occasionally, the Leephus. In Game 7 of the 1975 World Series, Lee twice retired future Hall of Famer Tony Perez of the Cincinnati Reds with the pitch. The third time Perez came up, however, Lee tried it again, only to have Perez hit a homer that set the stage for a Reds come-from-behind win of the game and the World Series. There were reports that Perez hit the ball so hard that the Boston outfielders didn’t even bother turning their heads to watch it fly. After the game, the ever-philosophical Lee quipped, “Live by the slow curve, die by the slow curve.”
Steve Hamilton of the New York Yankees was known for throwing the folly floater. He also developed a pitch called the hesitation hummer. This pitch started with the classic slow delivery of the “folly floater” but then would be “hummed” in as a fastball. The “hesitation hummer” worked with the “folly floater,” and contributed to Hamilton's modest success. Fans at Yankee Stadium, during the mid to late 1960s, loved to see Hamilton work these novel pitches in his relief appearances. One of Hamilton's most famous moments involving the "Folly Floater" occurred during a June 24, 1970 game against the Cleveland Indians. Hamilton threw the pitch to Tony Horton, who fouled it out of play behind home plate. Horton asked for another "Folly Floater," and Hamilton again threw one, and again Horton popped it into foul territory behind home plate—this time into Thurman Munson's mitt. Embarrassed, Horton crawled back into the Indians' dugout .
Pascual Perez, who was best known for his antics on and off the field threw his version of the Eephus during the late 80's and early 90's, which was dubbed the Pascual Pitch. On July 19, 1988, while playing for the Montreal Expos, Pascual made the mistake of throwing the Pascual Pitch to Glenn Davis of the Houston Astros. It just so happened that Glenn Davis was a former softball home-run leader, so he wasn't fazed at all by the pitch, and hit it into the upper deck down the left field line. The Astros won that game 4-3.
During a 5-hit performance by Ichiro Suzuki versus the Chicago White Sox on September 4th, 2004, Mark Buehrle, who has struggled facing Ichiro throughout his career, threw up an Eephus pitch during Suzuki's 4th at-bat. Buehrle later claimed that he'd tried every pitch in his repertoire against Suzuki and had resorted to making up new pitches in his futile attempts to get him out.
Dave Stieb was known to occasionally throw a form of the Eephus pitch, called the "Dead Fish".
Orlando Hernandez of the New York Mets has also been known to throw the Eephus several times throughout his career. In 2002, while playing for the New York Yankees, he threw one to Texas Rangers shortstop Alex Rodriguez, who hit it for a home run. He threw one on June 23, 2007 to strike out Oakland A's cleanup batter Eric Chavez, thereby preserving a 0-0 tie; the Mets went on to win that game in the bottom of the ninth inning on a double by David Wright.  On July 4, 2007, he threw two back-to-back Eephus pitches against Todd Helton of the Colorado Rockies with a 3-2 count and the bases loaded. Helton took a big swing at the first, just catching the top of the ball to foul it off. Helton merely watched the second pitch go by and took a walk.
Other nicknames for the Eephus pitch include the Bloop Curve, and Bugs Bunny
- San Francisco Chronicle article on the Oakland As mentioning Tadano throwing the eephus pitch in Spring Training Retrieved: 22 May 2007
- Video of Tony Horton fouling off Steve Hamilton's folly floater Retrieved: 29 June 2007
- MLB.com article