1) Fictional reptilian 
The Treens are fictional aliens in the Dan Dare stories. They first appeared in Dan Dare: The First Story, which was serialized in the Eagle comic magazine from Volume 1, Number 1 (April 14, 1950) to Volume 2, Number 25 (September 28, 1951). The story was drawn by Frank Hampson. ==Fictional background== The Treens are a race of green-skinned human...