Ancient Aliens

Ancient Aliens are those which have evolved billion years ago or earlier. While life on Earth was still on bacterial level, these aliens were already wandering through the cosmos; nowadays some are extinct while others remain.

In a more objective and less anthropocentric definition, ancient species might perhaps be defined as the product of the first and second generations of stars in our Universe (our sun is a third generation star). Some of these, however, may be even older than that.