Two powerful magnets connected by a tough rope. They are very heavy and should only be thrown by strong combatants. The bolas wrap around and stick to an enemy’s metal weapon and increase its weight, making it harder to use. Swings become powerful but random, possible doing more damage but certainly missing more.
A popular tactic for the Magnetic Bolas is to use them in a room with a metal floor, they must be thrown high to cover enough distance to reach the enemy weapon but, with any luck, the magnets will draw the metal weapon towards the ground. These can also be used as normal bolas for making ranged trip attempts and are actually quite effective because it is hard to free the magnets from each-others magnetic fields.
The Magnetic Bolas were created by a simple alchemist, who was the friend of a warrior, that wanted to help out a friend by trying something new. He knew about the properties of magnets and their uses, it was part of the alchemist training his master made him go through. So all he had to do was find magnets with enough pull and bind them together with strong rope and… viola! Magnetic Bolas were born.