"This is the part I like best!"
Bud during multiball, No Good Gofers
A multiball mode is a mode where more than one ball is in play. In real life, multiball started out as the primary objective of early 80s machines like Firepower and Black Hole; however, these had no associated scoring opportunities with them, like later pinball machines would have. High Speed is considered one of the first pinball machines with multiball-exclusive scoring opportunities.
In many Williams / Bally tables and on early Zen originals like Tesla, multiball modes are usually an optional mode that isn't required to reach and beat the wizard mode; just a different way to score big points. However, tables like Attack from Mars and Adventure Land have multiballs that must be started to reach the wizard mode; and tables like Star Wars: Han Solo have many multiball modes with concrete goals, all of which need to be completed to progress to the wizard mode.
The activation of a multiball mode also varies across tables. Normally, a multiball mode must be started by locking each ball at a certain area on the table. The lock shot is usually the same for every ball, but tables with several different multiball modes can have multiple, different lock shots. Tables designed by Zoltan Vari typically have "fast locks", ways to lock a ball in as few as one or two actions.
The multiball mode will usually start immediately after all balls are locked. If the multiball mode does not require the player to lock balls to start it, it is considered to be a quick multiball.
In most multiball modes on Zen original tables, there are certain lanes or targets that can be hit to award a jackpot, a large score reward which may or may not have a way of being increased. There may also be a way to earn a super jackpot, worth more points than a jackpot, but more difficult to earn. Williams / Bally tables will typically only light one shot for a jackpot, and require the player to maintain multiball while focusing on the jackpot shots.