The Atraxi are horrible Prison Guards
The Atraxi race is prison guards who guard 1 prisoner. This one escaped and headed through a Crack in time to Earth. The Atraxi travelled through the galaxy to find him. They sent a message to Earth telling them to hand over their prisoner called Prisoner Zero. They said if they don’t within 20 minutes as they will destroy the planet. They were able to do this by scanning the planet and detecting Prisoner Zero in a little place called Leadworth.
When the Atraxi communicated through the Crack in Amy’s bedroom wall there was only a eye say Prisoner Zero has escaped. Then when the Atraxi found Prisoner Zero they were still going to destroy Earth. Then the Doctor got his new clothes on and told them this is a level 5 planet which by order of the Shadow Proclamation this planet can’t be invaded. The Atraxi then fled and left Earth in peace.
Then the Atraxi returned and joined The? Pandorica Alliance , a group of monsters and aliens that River Song calls "Everything that ever hated you" who planed to, and succesfully, put the Doctor inside the Pandorica (The Pandorica Opens/The Big Bang)This happened at Stonehenge in 102 A.D which then the Atraxi after what the Doctor did to them wanted revenge. When the Doctor was inside the Pandorica the Tardis blew up and everything in the universe was destroyed including the Atraxi. Everything was put back right the Atraxi lived again as they might return for vengeance.