The worst thing someone has done to me while running was actually done beforehand -- someone set a booby trap on one of the hiking/running trails. They hung some fishing lines at face/neck height between two trees with several sharp pieces of metal hanging from the lines (fishhooks I think, I can't remember). I would have run right into it, but I happened to stop to wait for some slower runners a few feet away from it. I stood there for a few seconds and stared at it because I thought I saw something strange out of the corner of my eye -- it really took a few seconds of staring at it to realize what was going on. Really close call.
Cyclists have it way way worse than runners though.
One of my friends was riding his bike down a country road (in the US), a car passed him on his left, swerved in front of him, and slammed the breaks. My friend was taken by surprise and swerved to the left of the car to avoid slamming into it, at which point the car swerved to the left as well, into the oncoming traffic lane, and pushed him off the left side of the road. My friend was hospitalized for a long time and suffered brain damage from the crash. We knew what happened because another cyclist we knew happened to be on the road not far behind him (not riding with him) and saw the whole thing. The driver was an older man in his 50s or 60s, and his wife was sitting next to him in the passenger seat!
That reminds me of another time I was riding in the bike lane and the car to my left pulled into the bike lane as it pulled even with me and started slowing (we were going about 20mph). When I yelled at him (because I literally had nowhere to go -- I was breaking but cars can break better than bikes) he told me to "stop being a troll". He had two daughters in the car with him, one a teenager and one a little girl.
Another of my friends was riding down the street and some guy in his car tried to run him over. My friend hopped his bike up onto the sidewalk to try to evade the car, the car followed him onto the sidewalk and slammed into a pole on the sidewalk, wrecking the car.
Last month I was riding down the street in the bike lane and a car swerved into the bike lane about a foot in front of me, hit the breaks, and stopped. I almost slammed into it but got around to the left. There were several other cyclists behind me (rush hour in a big city), so they all started yelling at him, and he waved them off dismissively with the back of his hand. As I went by the driver's window (slowly because I'd hit the breaks to avoid him) I imitated his wave, so he threw open his door at me to try to hit me (the door hit my back wheel and just pushed me forwards a bit), got out of his car, and tried to fight me. I rode off as several other cyclists stood there yelling at him and he tried to push past them to get to me.