i hit my head on the bottom of this pipe and nearly cracked my head open and had my brains fall out. actually it didn't even bleed. but there was a bump. and it hurt. i have hit my head a lot over the course of my life. one time when i was working at fedex i hit my head on a low beam and it was bleeding and even scalped me a little bit. it was very gross and i never told anyone because i was embarrassed.