Amulet of spells

A small golden amulet with in the center a red gem that glows.

This amulet absorbs every spell that is cast by the wearer. So if a barbarian wears it, it will do almost nothing while if a mage wears it, its gonna be the most dangerous item ever.

All the spells will be released from the amulet when its removed and a specific word is said in a gaint fury of spells in the form of a bom.