Five ornery bulls gored four revelers — including a Philadelphian — and injured five others with cuts and bruises as they hurtled through Saturday's San Fermin festival in the northern Spanish city of Pamplona.
One bull charged into runners, goring one deeply in a thigh while cutting another runner's leg as it lifted its head.
Red Cross spokesman Jose Aldaba said four people received treatment after being gored while at least five others were recovering from sprains, bruises and — in one case — a broken collarbone.
The Americans — both men — were a 34-year-old from Philadelphia identified only by his initials J.N.O., who suffered two gorings, one behind his knee and another near the anus, and a 20-year-old with lesser injuries identified as A.G.O., the regional government said in a statement.
Kiko Betelu of the Navarra region's medical service said three of the gorings were simple to treat, but one of the injuries was deep and required surgery.
Normally six bulls run in the San Fermin festival, but on this occasion Curioso — a 1,180-pound (535-kilogram) beast belonging to the Jose Escolar breeding ranch — later had to be transported to the ring to join the other five.
Unlike the gentle, flower-sniffing Ferdinand, Curioso — which means curious in English — almost certainly won't get a chance to retire.
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According to San Fermin experts commenting for state television TVE, the last time a bull turned back to the holding pen was in the 19th century.