Mountain Crusher was eight feet long. It was strung with woven steel cord. It was reinforced with the ribs of a glacier bear, allowing Tavis to use his incredible firbolg strength to best effect without risking snapping the weapon. The bow was covered in runes, which were etched by Tavis' runecaster companion, Basil of Lyndusfarne.
The weapon was a +5 composite longbow, which allowed Tavis to apply his full strength to his attacks. When Tavis said, "Basil is great," backwards, one of the runes on the bow would glow a ruby color and then vanish, granting the bow its magical power. An arrow shot from the bow would leave a trail of crimson behind it as it flew.
Mountain Crusher was specially crafted for Tavis, after his first bow, Bear Driller, was broken in Tavis' battle with Arno and Julian. It received its name from Queen Brianna after Tavis used the weapon to create a landslide which trapped a group of fire giants in the Gorge of the Silver Wyrm.
Tavis wielded his bow frequently in combat, using runearrows from Basil as ammunition.