Welp, there's not a whole lot of explanation required for this one. Apparently, a high school physics teacher thought it would be a good idea to conduct a class-wide demonstration that featured a cinder block and an axe. Yes, an axe. Rather predictably, the whole thing went awry and this poor guy ended up catching the business end of a teacher's swing as though he were a rotting maple tree. 

Now, there seems to be some confusion regarding the details of this incident. While many publications are pitting teacher versus student, a report from the Daily Dot cites a Reddit user as saying he was there during the incident and that the person being hit is the teacher. The axe wielding mad man is identified as also being part of the school's staff.

Also, not trying to pile on because I'm sure this guy is having the worst week of his life, but the victim is at least 50-percent culpable for participating in the first place. If your teacher asks for "volunteers" while carrying an axe and a cinder block, you need to book it out of the classroom and never look back.