I like a good practical joke as much as the next guy, but the humor of the “Oh noes! I’ve injured myself grievously! Ha ha!” practical joke is that you didn’t actually injure yourself! Here is an example of how not to do it:
Police got a call just before 5 a.m. Sunday from a 21-year-old man who said his friend fell off the Highway 77 bridge and into a marshy area about 30 feet below. The caller said he was driving north when his friend, who he said had been drinking, told him to pull into the bridge’s emergency lane so he could urinate.
The 23-year-old eventually climbed to the ledge of the bridge, then looked at his friend and pretended to fall. “He then in fact fell,” reads a press release from the Bloomingtin Police Department.
It also probably helps if you’re not drunk when trying to pull the prank.