Mataelpino is a small town near Madrid in Spain, that recently held the “Running of the Balls” or “Boloencierro,” a cruelty-free version of the Spanish festival involving bulls, using 300 kg (661 lb) resin balls instead. While the event was supposed to be loads of fun, two people were seriously injured when hit by the massive ball.

‘Running of the Balls’ in Mataelpino

The small town of Mataelpino decided seven years ago to do away with the cruel “Running of the Bulls” festival, similar to the one held in Pamplona in Spain where people run ahead of a bunch of bulls down the narrow streets.

The mayor of the town came up with the “Running of the Balls” instead, so people could still have fun, but without any animal cruelty involved.

Many other towns followed them in changing over to balls instead of bulls and the event has started attracting visitors from all over the world. For effect, the giant balls are painted with bull faces and rolled down 500 m (1640 ft) of the sloping and narrow streets of Mataelpino at speeds of approximately 20 miles per hour, while participants run madly ahead of them. Readers can get a better idea of the size of the ball from the tweet below.

While in past years, the event had been successful and loads of fun, attracting more visitors each year, this year’s "Running of the Balls" festival turned into a tragedy.

As reported by the Telegraph, one participant suffered a skull fracture when crushed between the resin ball and a metal barrier in the street and is now in an induced coma. A second man also had a bad encounter with a ball and has three broken ribs and a concussion. The incident can be viewed in the video below.

Mayor to review safety protocol for the 'Running of the Balls'

Mataelpino Mayor Javier Pérez de los Nietos, who originally came up with the idea of the “Running of the Balls,” said in a statement after the incidents that safety protocol will now be reviewed by the municipality before next year’s "Boloencierro" event. However the mayor went on to warn participants to take things a little more seriously. He pointed out that while there are no thundering bull hooves or sharp horns, the balls can be equally dangerous.

The mayor said anyone used to running with bulls knows that they can’t just stop and stand in front of them, because they would be gored.

People think nothing can happen to them if they do the same with a ball, but it turns out this isn’t the case – a direct hit from the ball can be pretty serious. The mayor stressed that they don’t want the fun "Running of the Balls" festival to end up being a tragedy.

El Mundo reports that authorities are considering lowering the height of the metal barriers, to make it easier for participants to escape the approaching balls. They are also recommending that people wear gloves to avoid suffering abrasions during a fall. They may also consider using lighter balls, similar to those currently used in children’s events in Mataelpino, to prevent injuries.