Borderlands 3: Psycho Krieg and the Fantastic Fustercluck

Description
Fourth and last expansion included in the Borderlands 3: Season Pass with unchanged premise - therefore the player controls one of the Vault Hunters from the base game, eliminate psychos and gather loot. Game expands this by offering new weapons, enemies and locations.
Plot-wise, game is centered around psychos, one of Borderlands series most recognizable enemies. According to Patricia Tannis, fact that these enemies are "unitary insane" is caused by a knowledge about a place called Vaulthalla. Tannis tried to recover that information by asking Krieg, which appeared in one of the Borderlands 2 DLC's, however his answers were not relevant to Patricia's question. Therefore, she decided to create a device, that allows to enter Krieg's mind and after doing so, she sends there the Vault Hunters. There they must try to find that answer on their own.