Blackblood

Blackblood is a magical club +3, which has the normal bonus of +3 to damage and thaco, but also deals +3 acid damage every time it hits the target, which makes it an excellent weapon for druids to slay trolls. This club has a weight of 3 lbs, a speed factor of 4 and it requires a strength of 5 to be wielded. Blackblood is sold in Trademeet by an unnamed merchant after the genie problem has been solved. This item appears Baldur's Gate II: Shadows of Amn, in which this a powerful club.

In-game description
"Club +3: Blackblood. This oak club is coated with darkened dried globs of a tar-like substance. During battle this substance glows black with an inner light, and becomes thick and fluid. When the club strikes an opponent it delivers additional acid damage from the liquid splashing over the victim."