Gintama.: Slip Arc
Gintama.: Porori-hen · 銀魂. ポロリ編
Synopsis
Consists of episodes animated from unused manga chapters, before returning to the Silver Soul Arc on January 8, 2018. Porori is an Onomatopoeia for something (mainly water) falling.
Studios: Bandai Namco Pictures, Aniplex
Source: MANGA