Weapons come in all shapes and sizes and uses. A Retiarius Net may not seem like a weapon, but when you use it to trap your enemies so you can then kill them, it seems pretty deadly. FYI, impaling the enemy with a Trident is one of many killer options your minifig has. 

Dress up like the killer gladiator on the left with a Tribal Mask and Tribal Plume. Dress like the gladiator on the right with a Do Rag, Arm Guards, and a Retiarius Galerus.