Interesting thing about nosebleeds. When I was in high-school, during the winter here in Florida I would occasionally get a nosebleed due to the air being cold and dry. One time at school, I was eating lunch when I felt something 'off' in my nose, so I knew it was about to bleed. I left my friends saying I'd be back (they didn't realize I had a nose bleed because I was sniffing in each time I could feel the blood threatening to exit my cursed nostrils) and then I headed towards the bathroom. After 15 minutes went by I couldn't get it to stop, so I decided I'd mess around and make a foe-crime-scene type thing to freak someone out. I blew out of my nose as hard as I could onto parts of the wall, floor and sink. I then took a plastic knife I had from the unused plastic-set I had in my pocket and put some blood on that too, dropping it onto the floor (but being sure not to touch it with my hands).
I then finally got my nose to stop about 5 minutes later and headed out to class. About half an hour later, I see police officers scouting the school and an alarm code is spoken through the loud-speaker. We were put on lockdown for 4 hours and police came to each room to check attendance sheets and ask if anyone knew someone who may be hurt. Of course, nobody knew of anyone who was, and they eventually left.
I did get to pet their German Shepherd, though, as the officer stood with his dog near my desk as it was closest to the door. I fuckin love German Shepherds.