Mexican Monsters Under The Bed?? Info Needed.?

Okay, when I was tiny, my mami would tell me that there was a monster that lived under my bed. She said if I got up out of bed or misbehaved that it would come out and eat me. She said it would watch me all the time. I'm half Puerto Rican, but my old papis' friends were all Mexican and he imilated into their culture so I think it was a Mexican thing. I think it started with a C... or a K... Or a cuh sound. Like cuhcuhcooey. Like wtf. Anyone know what this is?? Can I get a little information on it.