Answer by taking a quote from the following article:

Earvin "Magic" Johnson Jr. (born August 14, 1959) is an American retired professional basketball player and current president of basketball operations of the Los Angeles Lakers of the National Basketball Association (NBA). He played point guard for the Lakers for 13 seasons. After winning championships in high school and college, Johnson was selected first overall in the 1979 NBA draft by the Lakers. He won a championship and an NBA Finals Most Valuable Player Award in his rookie season, and won four more championships with the Lakers during the 1980s.

In 905 NBA games, Johnson tallied 17,707 points, 6,559 rebounds, and 10,141 assists, translating to career averages of 19.5 points, 7.2 rebounds, and 11.2 assists per game, the highest assists per game average in NBA history. Johnson shares the single-game playoff record for assists (24), holds the Finals record for assists in a game (21), and has the most playoff assists (2,346). He is the only player to average 12 assists in an NBA Finals series, achieving it six times. He holds the All-Star Game single-game record for assists (22), and the All-Star Game record for career assists (127).  Johnson introduced a fast-paced style of basketball called "Showtime", described as a mix of "no-look passes off the fastbreak, pin-point alley-oops from halfcourt, spinning feeds and overhand bullets under the basket through triple teams." Fellow Lakers guard Michael Cooper said, "There have been times when [Johnson] has thrown passes and I wasn't sure where he was going. Then one of our guys catches the ball and scores, and I run back up the floor convinced that he must've thrown it through somebody." Johnson could dominate a game without scoring, running the offense and distributing the ball with flair. In the 1982 NBA Finals, he was named the Finals MVP averaging just 16.2 points, the lowest average of any Finals MVP award recipient in the three-point shot era.  Johnson was exceptional because he played point guard despite being 6 ft 9 in (2.06 m), a size reserved normally for frontcourt players. He combined the size of a power forward, the one-on-one skills of a swingman, and the ball handling talent of a guard, making him one of the most dangerous triple-double threats of all time; his 138 triple-double games are second only to Oscar Robertson's 181. Johnson is the only player in NBA Finals history to have triple-doubles in multiple series-clinching games.  For his feats, Johnson was voted as one of the 50 Greatest Players of All Time by the NBA in 1996, and was inducted into the Naismith Memorial Basketball Hall of Fame in 2002. ESPN's SportsCentury ranked Johnson #17 in their "50 Greatest Athletes of the 20th Century" In 2006, ESPN.com rated Johnson the greatest point guard of all time, stating, "It could be argued that he's the one player in NBA history who was better than Michael Jordan." Several of his achievements in individual games have also been named among the top moments in the NBA.

what was showtime about?
a mix of "no-look passes off the fastbreak, pin-point alley-oops from halfcourt, spinning feeds and overhand bullets under the basket through triple teams.