Just in time for Halloween, NASA’s Hubble Space Telescope has spied the ghostly remains of galaxies that were ripped apart billions of light years away a long time ago.

The telescope captured an eerie blue light in Pandora’s Cluster, a group of 500 galaxies. That light comes from orphaned stars hurled into space after six galaxies collided long ago, according to a recent NASA statement.

The celestial massacre took place over 6 billion years in the cluster, which is 4 billion light-years away.

The data provides insight into the evolution of galaxy clusters, researchers said. The parent galaxies were essentially “pulled apart like taffy,” NASA said in the statement, and the eerie light will help scientists find out what happened within the cluster.

They estimate that there are 200 billion orphaned stars in Pandora’s cluster alone, making up 10 percent of the light emitted by that cluster. It took scientists three years of observations to identify the glow.

Essentially, the stars are no longer bound to a galaxy and simply drift between galaxies.

The galaxies that were torn apart were probably as big as the Earth’s own Milky Way Galaxy. The galaxies were ripped apart by plunging into the center of cluster, where gravity is the strongest. Although researchers expected it would find light from those stars, it was very faint and difficult for scientists to spot.

Scientists used Hubble’s infrared sensitive to very dim light in order to spot the glow. The stars are rich in elements such as oxygen, carbon, and nitrogen, meaning they are second or third-generation stars containing elements from the universe’s first genration of stars.

The results were published in the Astrophysical Journal.