+2 Ebonstone Greatsword of Collision

Description
This powerful Greatsword of Chozo design was recovered by Tal Marrow from a tomb on the deepest floors of Agon Temple. On top of being a potent +2 magical weapon, it also has the Collision psionic weapon quality, giving it an extra +5 damage for a total of +7.

Beyond this, the sword is also made of the incredibly durable Ebonstone material. In practice, this means it has the same properties as Adamantine, such as ignoring Hardness up to and including 20 and certain types of Damage Reduction. In addition, it is also virtually impervious to certain types of damage. It is immune to Cold, Fire and Electricity, and resistance 30 to Acid and Sonic. Note that these qualities only apply to the weapon, not to its wielder.