(c) 1996 National Dairy Council. Click to see a copy of the ad for sale at BambooTrading.com.
There was a much funnier strip in the original comic series of The Phantom by Lee Falk, who died in 1999. If I had to guess, I'd place it between 1986 and 1992 - say, 1989 plus or minus three years. The strip involves The Phantom, in full costume, going into a bar where a bunch of tough customers are sitting. They order various forms of liquor and he orders a glass of milk. After he brushes off their mockery, they attack him, with the expected results. Apparently he doesn't use his Mark of Evil on them, because instead of bemoaning their permanent scarring, they join him in... you guessed it, ordering milk. The Phantom then breaks the fourth wall and raises a glass at the reader.
Does anyone remember this strip? I would be most grateful to see it again.