Kirk Gibson Jr. Slugger 2000 adjustable bat

From Futurepedia, the Back to the Future Wiki

Griff lines up to swing.

"Batter up!!!"

—Griff Tannen to Marty

The Kirk Gibson Jr. Slugger 2000 adjustable bat was a bat manufactured in the 21st century that was named for a baseball player that won a memorable World Series game for the Los Angeles Dodgers in 1988. The bat could be easily hidden and carried in its compact form, and could automatically extend itself like a telescope to almost twice its original length.

Griff Tannen possessed one of these bats in 2015 and extended it for use during his exchange with Marty McFly, whom he believed was Martin McFly Jr. Griff swung frantically at Marty only to hit the simulcra screen and the taillight of his BMW 633CSi. He used the bat one last time to swing at Marty while over the water in Courthouse Square, but missed when Marty jumped at the last second.

[edit] Behind the scenes

Kirk Gibson Jr. was on the minds of baseball fans during the time Back to the Future Part II was written due to his heroic effort that helped win the 1988 World Series for the Los Angeles Dodgers. Stepping up to bat as a pinch hitter with two injured legs, he hit a home run from Oakland Athletics relief pitcher Dennis Eckersley, marking the first time a World Series game ended with a come-from-behind home run. The Dodgers would go on to win the World Series in five games.^[1]^[2]

Another improbable come-from-behind win was achieved by Jim Decker during the football game played by UCLA vs Washington, November 12, 1955.