A Macuahuitl is an Aztec weapon that was a wooden club with several embedded obsidian blades. It was a thick, three- or four-foot wooden club spiked with a number of blades made from obsidian. Obsidian is a naturally occurring volcanic glass formed as an extrusive igneous rock. Obsidian is produced when felsic lava extruded from a volcano cools rapidly with minimal crystal growth. Obsidian is capable of producing an extremely sharp edge, sharper than high quality steel razor blades.
This weapon was likely the most feared weapon used by Aztec warriors both before and during the era of Spanish conquest in Mesoamerica starting in the 15th century. It was known that when the invading Spanish found themselves up against the Aztec warriors branding their Macuahuitl they kept there distance from the Aztec warriors and their menacing weapon.
The blunt portions of a Macuahuitl could knock someone unconscious. This would allow Aztec warriors to then drag the victim back for a ceremonial human sacrifice to their gods. Those sharp Obsidian blades however did some serious if not deadly damage they were sometimes serrated for maximum . Much like the teeth of a chainsaw, the obsidian blades framing the paddle were notched to inflict as much pain to the victim as possible. Not only would the skin easily slice, but it would also rip and shear off the body when the Macuahuitl was pulled back.