Barrel of Bwoosh!

The Barrel of Bwoosh! is made

Explosive material taken from Caelar's crusaders at Boareskyr Bridge were refined by Phossey Dugdeep in Chapter Ten – Allied Siege Camp of Baldur's Gate: Siege of Dragonspear.

The Stone Dowser must be worn as a necklace to properly guide Gorion's Ward and Companions to the Barrel of Bwoosh! drop site on the Underground River map. The drop site is south of the Ettin Ghost.