This one starts with my house in the ocean (I think?). But I'm walking around and talking like it's nothing. Then I drink a glass of water (????) and start floating. This happens because the water I drank is less dense than the water around me. (That is literally what I was thinking at the time.)
There was also something about a weirdly edited version of the Pink Elephants sequence from Dumbo playing on TV, but I was much more interested in my impromptu physics lesson.