Dagger +2

Dagger +2 is the standard enchanted dagger, but it has the same stats as the Heart of the Golem, which is also a +2 dagger. It can inflict 1d4 +2 points of piercing damage, has +2 thaco bonus, a weight of 1 lbs and a speed factor of zero. This item appears in Baldur's Gate II: Shadows of Amn. It's not known where this dagger can be obtained.

In-game description
"The typical dagger has a pointed, double-edged blade, as opposed to a knife which has a single edge and is a bit shorter. This particular dagger is magical, having special bonuses to its speed, accuracy, and damage it causes.  Also, since it is magical, is it capable of striking opponents that are immune to normal weapons, such as vampires, elementals and mummies."