Ecosystem in a bag of holding

[Sstoopidtallkid]

We once used a necklace of adaptation to keep a minotaur in a portable hole. We were found of saying "I choose you, minotaur of doom"

Then we forgot about him for a month, and the necklace of adaptation ran out of air.

There's nothing quite like being able to drop a Gelatinous Cube in your path to slow pursuers.