Slimes produce Slime Balls, and do so only when given access to water via the troughs in the Slime Hutch. There must be either one male and one female slime or at least five slimes of one sex present before Slime Balls can be produced. The Slime Ball can be right-clicked to release multiple Slime items. These piles of slime have a chance of appearing daily, much like the products of coop animals.
Slime balls also have a rare chance to have Petrified Slime inside.