El Chupaespada is a cryptid of legend, that skulks through the night looking for stray swords. It sucks on the metal, absorbing as much of it as it can, leaving behind nothing but crumpled up daggers. As it feeds on the metal, its own bones and spines grow stronger, longer and sharper - a fully gorged Chupaespada can grow to the size of a bull and is ten times as ferocious.
Luckily, they mostly prefer to stay hidden and only fight when they need to. Many blacksmiths will simply sate them by leaving lower quality swords in the easiest places for an El Chupaespada to find them.
Mentioned in Hellswing's Cryptid Casefiles. See: hellswing