Disaster struck a street party called Deltopia when it turned violent after a police officer was struck in the head with a bag containing bottles of alcohol; over 100 people were arrested during the spring party in Isla Vista in Santa Barbara.

At least 15,000 people gathered in the celebration, most of which are thought to be college students from the University of California. The disturbance started after a police officer was struck in the head with a bag full of alcohol. When the authorities tried to arrest the suspect, objects including bricks, and bottles at them, according to CNN.

To contain the riot, police threw tear gas, pepper spray, flash bang grenades, and foam projectiles at the crowd, according to LA Times.

Many party-goers tweeted about the party, and the crazy night the ensued, using hashtags like #deltopia2014.

One tweeter captioned her picture, “#deltopia in Santa Barbara pulled a project x party it started a riot.”