Hound of Hades

Explanation: Kerberos is a small moon of Pluto that was discovered by the Pluto Companion Search Team using the Hubble Space Telescope on June 28, 2011, using the Wide Field Camera 3, during an attempt to find any rings that Pluto might possess. The convention for naming Plutonian moons is to use names associated with the god Pluto in classical mythology. Kerberos is the Greek form of Cerberus, the dog that guards Pluto's underworld.

Pluto

Image credit: www.theoi.com.