PAMPLONA, Spain — A rogue bull gored a young Spaniard in the neck Friday, the first fatality in nearly 15 years at Pamplona’s running of the bulls. The victim was killed almost instantly as he scurried for cover under a wooden barrier, sliding under it feet-first.

For a bull, this one was on the smallish side, at just over a ton. And its name, Capuchino, sounded harmless enough, like coffee with frothy mi...