The fine white froth around the lips that is a characteristic of drowning victims. This definitely seems like a candidate for someone's (reesetee's?) "worse than it sounds" list. Most of the google hits for this term are gastronomic in nature, but there is a pretty delightful link to googlebooks:
I came across this indirectly while reading Ben Macintyre's "Operation Mincemeat"; in a discussion of the problems associated with faking a drowning victim, he refers to this particular symptom, but gets it wrong, calling it "champagne de mousse". It took a while to track down the correct term.