Bag of Beholding

Disclaimer! This item exists solely for the purpose of inflicting real life psychic damage onto my DM and has not been play tested at all, since it would result in a catastrophe.

A bag appearing visually to be like any other bag of holding. It contains exactly one Beholder and nothing else. You cannot add anything else inside the bag. The creature sleeps until the bag is opened at that point the one opening the bag must roll an intelligence saving throw at which point it may awaken in one of two orientations: 

1- 11. Facing away from the opening: If the Beholder awakens facing away from the opening, its antimagic vision fills the interior of the bag. The antimagic suppresses the magic that creates and maintains the Bag of Holding’s extradimensional space. The space collapses because the Beholder is too large to fit in a nonmagical bag, destroying the bag and expelling the Beholder and any contents into the surrounding space. The Beholder attacks whoever was holding the bag last.

11-20. Facing the opening: The Beholder lashes out immediately, attacking any creature near the opening using its eye rays. Afterward, it returns to sleep.