A migrant wave and a Hydra Megabeast both showed up within thirty seconds of each other and in the exact same spot of the map. The Hydra had a great deal of fun slaughtering the incoming migrant workers, who just kept on appearing on the map as if they were sides of beef delivered by conveyor belt.
Than a heroic hunter dwarf, who was hauling back a giant thrips corpse, spotted what was going on and engaged the Hydra in an attempt to save the remaining migrants. It promptly bit his head clean off his shoulders. The next migrant to appear was a Blacksmith with no training in combat whatsoever. Running up to the body of the hunter and grabbing the crossbow out of its hand, the Blacksmith turned to engage the Hydra with her pilfered weapon.
With no bolts to fire and no idea what the f-ck she was doing, the Blacksmith charged the Hydra and smashed the copper crossbow down onto its foot, crushing the bone. Sidestepping away from the counterattack, the female Blacksmith ducked around behind the Hydra and smashed the copper crossbow into its spine, shattering the bone and rendering it paralyzed from the waist down.
It took several minutes for me to get my military dwarves up to the surface as I had them prowling the caverns when the Hydra arrived. By the time they arrived the female Blacksmith had shattered four of the Hydra's seven skulls and had broken most of the bones in its body, all without suffering a single injury herself. She has since been put in charge of her own squad, in the hopes that her abilities would rub off on my freshest batch of recruits.