Move over brass knuckles, mace, and knives, it appears another weapon has emerged as a street fight staple: A bloody maxi pad.

Though it’s unclear what started this mid-road showdown, it’s apparent that one participant decided to come very prepared to brawl, reaching down into her black leggings and fishing around before finally unsheathing her DIY shield — a blood-soaked sanitary napkin.

Newly armed, the woman wasted no time in giving her opponent a (very metallic) taste of her fury, hurling the pad directly at her head.

Despite the biohazard of it all, the adversary decided to fire back, plucking the dirty pad off of the ground and throwing it right back. Reunited with her favorite weapon, the woman saw an opportunity, rushing back and proceeding to beat her opponent with the pre-blooded shiv.

If there’s one lesson to be gleaned from this messy debacle, let it be this: When you mess with a woman on her period, there’s a good chance that there will be blood.