Moose Missing Mojo

Moose has been acting quite strangely the past couple of days-- as best I can figure, he caught the smell of something late last week which freaked him out. Now he is reluctant to go outside (if you know Moose, you know how unlike him that is!), and when he is out, he is very nervous, tail between his legs, glancing furtively side to side. And he is eager to get back into the house. Very strange... Any theories from the "blogosphere" on what could have caused this ?

Seems a bit better today... we'll hope he's back to normal soon.