...To Be Left Alone

...To Be Left Alone is a challenge in Risk of Rain 2.

It unlocks the character Acrid, added in the Hidden Realms update. This challenge is completed by completing a wave-based challenge in the Void Fields, a Hidden Realm found by activating the Null Portal in the Bazaar Between Time.

Trivia
The name of this challenge refers to the ending quote from Risk of Rain when completing the game as Acrid. The entire quote is "...and so it left, with a new hunger: to be left alone."