Mighty Oak

Mighty Oak is a club +2, which has the normal bonus of +2 to damage and THAC0, which makes it an excellent weapon for druids. This club has a weight of 3, a speed factor of 2 and it requires a strength of 5 to be wielded. Mighty Oak is dropped by the leader of the Shadow Druids Amarande in the treehouse in Cloakwood 3. Jaheira must be present in the party for Amarande to attack.

In-game description
"Fashioned from the hardest old oak from the High Forest, this gnarled cudgel can fell an adult grizzly when wielded by a skilled warrior."