He seemed pretty powerful, he's a few links. Maybe it'll give you guys a few ideas.
http://en.wikipedia.org/wiki/Antaeus
http://ancienthistory.about.com/cs/herc ... ntaeus.htm
http://www.pantheon.org/articles/a/antaeus.html
So what I can assume by this is that he's either weak to wind based attacks or choke?
Or maybe you have to move him from his location somehow?
-edit-
Fairy rings didn't really reveal anything in particular
http://en.wikipedia.org/wiki/Fairy-ring_Mushroom
night time only?