The Ashtanga are battleships created by the Anti-Spiral to cull the population of Spiral lifeforms and antagonists in Tengen Toppa Gurren Lagann. Their purpose is to annihilate any Spiral lifeforms that manage to reach the Anti-Spiral's dimension. They are capable of deploying smaller ships shaped like disembodied hands and feet called Hastagrays and Padas.
After Team Dai-Gurren fought off the attack by the Mugann to destroy all Spiral lifeforms on Earth, they headed off for the Anti-Spiral's home dimension in order to defeat it and liberate the universe from its oppressive hold over Spiral life. There, in Anti-Spiral space, Team Dai-Gurren encountered the Ashtanga, the Anti-Spiral's battleships, who attacked them in an attempt to drive them back to Earth and cull their population once more. However, the Ashtanga were all destroyed by Super Galaxy Gurren Lagann, allowing Team Dai-Gurren to proceed on to the Anti-Spiral itself.
It is later revealed by the Anti-Spiral that Team Dai-Gurren's victory over the Ashtanga was intended by it so once they were defeated, they would feel despair over having failed after they had gotten so far.