Wondrous Item, uncommon
This tank has an interior space considerably larger than its outside dimensions, roughly 8 cm in diameter and 30 cm long. The tank can hold up to 250 kg of liquid and/or gas, not exceeding a volume of 2000 liters. The tank weighs 5 kg, regardless of its contents. Opening the valve of the tank requires an action.
If the tank is overloaded or pierced, it ruptures and is destroyed, and its contents are spilled into the Astral Plane.
Placing a tank of holding inside an extradimensional space created by a handy haversack, portable hole, or similar item instantly destroys both items and opens a gate to the Astral Plane. The gate originates where the one item was placed inside the other. Any creature within 10 feet of the gate is sucked through it to a random location on the Astral Plane. The gate then closes. The gate is one-way only and can’t be reopened.