here be dragons

phrase2

1. •
   A fanciful notation, commonly attributed to historical maps, held to indicate either the belief that unknown dangers exist in a certain location on the map, or that actual dragons can be found there.

   • It's like in those old maps of the world, where the mapmakers wrote, "Here be dragons" on the unexplored parts of the globe. — 1994
2. •
   By extension, used to indicate that which is unknown or uncertain, particularly if it seems to carry some type of risk.

   • Here be dragons in the shape of London landladies, owners of small hotels ('B. & B.') in the streets off the lower end of Euston Road. . . — 1962