They were effected by the moon
Wildly foolish.
A lunatic is someone who is very crazy or insane. They are people whose actions and manner are marked by extreme eccentricity or recklessness.
Is was thought that the Moon affected insane people, which is why the word Lunatic contains Luna which refers to the moon. It used to be believed (and some people still do believe) that moonlight...
lunatic(n) one who is insane/crazy/foolish.