The Erebus Supernova was a huge supernova that destroyed the original Valkyrie colony decades ago in the Polaris Galaxy. However, some Valkyries managed to survive and took residence on planet Vapedia. During the events of Ratchet & Clank Future: A Crack in Time, Nefarious agreed to help the Valkyries by using the Great Clock to prevent this if they helped him reach it. The Valkyries soon agreed, but the three Valkyrie leaders, Cassiopeia, Carina, and Libra were later destroyed; thus Nefarious betrayed the Valkyries. Without Cassiopeia, he no longer had any reason to help them, so nothing in the past was changed. According to Galactic Trivia, the Erebus supernova was the largest supernova in Polaris history.
- It is heavily implied, but not explicitly stated, that the Erebus Supernova was the resulting explosion from the tear in space-time created by the Fongoids' collective misuse of time travel, as said result destroyed eighty-three celestial bodies and, given the Fongoids' homeworld of Torren IV, most likely occurred within the Polaris Galaxy. This is further backed up by a late-game Space Radio news report, with reporter Kip Darling stating that the "time-space catastrophe" occurring across Polaris had been "unseen since the Erebus Supernova of late".
- In Greek mythology, the word "Erebus" refers to the primordial god of darkness, and translates to "shadow" or "deep darkness". Assuming that the Erebus supernova and the cataclysm created from the Fongoids' misuse of time travel truly are one and the same, this name may represent the untold destruction that came as a result of it (as the destruction of celestial objects across the galaxy would cause space to visually become "darker"), or how it "cast a shadow" over the universe's longevity, as the universe from that point onwards would need the Great Clock to maintain it.