Queth

 was the home planet of the Queeth. The Fifth Doctor, Tegan and Gravis unintentionally landed on Queth when they were trying to take Gravis to Kolkokron.

According to the Queeth, every planet their species had ever inhabited was destroyed by their unseen enemies. The Doctor discovered that they had only ever lived on Queth, and that it was caught in a loop that caused its destruction over and over again. The destruction was caused by the Queeth themselves. (PROSE: Life After Queth)