Arkonzynes are predatorial animals that invaded the moon in 1969.
After the Arkonzynes invaded the moon, they ate any Astronauts that came to the moon. Famous astronauts Neil Armstrong and Buzz Aldrin got lucky, as they were leaving as soon as the Arkonzynes arrived.
The Doctor, Amy and Rory encountered the Arkonzynes in the 1970s, but they had already met the Arkonzynes. The Arkonzynes later re-encountered them in the 2010s, but they hadn't met the Arkonzynes yet.