Ever had a lucid dream? If you’re not familiar with the term, it’s a dream where you are fully conscious and can exert influence over the dream. (Yes, you can be asleep and conscious at the same time.)
As this squid points out, looking at one’s hands is a good way to check if one is in a dream or not. In waking life, one’s hands look like, well, hands. But in a dream one doesn’t have hands — it tends to be a dead giveaway that one is dreaming when one look at one’s hands and they disappear or are unstable.
Just to be clear, however, this is not a lucid dream. The squid is messing with your head.
(Spotted at 18th and Valencia.)