[rktman]

Illegal aliens? Space aliens that is.

[AnAmericanMother]

Nope, just a creative bunch of folks with lots of time on their hands and materials available (in the case of most of Sussex, lovely green turf with bright white chalk right underneath).

My personal favorite (not really safe for work) with editorial comment by Homer Simpson:

Homer chalk giant angers pagans

Anything that "angers pagans" is probably a good idea.