The original 2nd Edition entry from the Forge.

Last Resort is a dagger with special powers in the hands of a wizard. In the hands of a mage, it acts as a dagger +2 and allows the mage to attack with the Thac0 of a Rogue of the same level. In the hands of any other class of character, the dagger serves as a +1 dagger.

If used to attack by a mage with no spells memorized, the dagger will cause the loss of 1/2 of the victims total hit points. If the victim makes a successful save vs. death, he only suffers 1/4 his total hit points of damage. The power of this dagger will only function once per enemy.