Perhaps it could scent our alien odor.

A faint alien odor permeated the room.

Controller then learned of soiled tailoring and alien odor.

I listened, tried to sniff any alien odor (though scent is the least of all warning for my species).

He could sense that the shell was gone, and there was an alien but earthy odour in his nostrils.

There was the reek of alien odours and an alien muttering.

It was an alien odor, the smell of body chemistries that were not human in origin.

I hoisted the sack back on my shoulder, and as I did so I caught the faint edge of the alien odor once again.

Strange birds were singing outside the open doors that let in the western breeze with its alien odors.

The horse and human scent filled its head, an alien odour it had never smelt before, but which reeked of danger.