Umbris was a planet in the Solana Galaxy. The planet had a highly explosive core which if destroyed would take out all of the planets in the galaxy along with it.
Ratchet & Clank
The planet was a target suggested by Dr. Nefarious to Chairman Alonzo Drek though he really just wanted the whole galaxy to be destroyed under the Ranger's watch and for his own personal gain. Ratchet, Clank and the Rangers managed to tilt the Deplanetiser so it would miss it's target and instead ultimately destroy the new homeworld built by the Blarg, New Quartu. Nefarious along with the Deplanetiser had crashed landed onto the planet however Nefarious survives this and a group of repair bots find him under the wreckage where they proceed to repair him to his dismay.