In 1970 my little brother was in the Air Farce in Okinawa. Some of his buddies convinced him to come snorkeling and shark hunting (with a powerhead -- a .45 caliber cartridge slammed against a shark by hand). So he did.

Swimming out about 200 yards he jammed the powerhead against a shark about six feet long, tied onto the tail, and swam to shore with it.

When he got to shore only the tail was left and the other sharks were swimming away.

THAT was something he only did once.