I'm looking for that manhwa(?) It's a supernatural phenomena where people suddenly turned ...

I'm looking for that manhwa(?) It's a supernatural phenomena where people suddenly turned into monster out of the blue, then there's this mc who's able to communicate with the monster and the monster is drawn to their blood because it's sweet and can actually wake them into oblivion, also the first arc took place in school where the 'special police' was demonstrating or teaching something to the class by showing a small cocoon, but then all went into chaos because someone accidentally spilled blood into the cocoon, Pleaseeeeehelp me find it!!