No, but it does look real.
Its all due to the sodium (i.e. salt) in the soy sauce, that flows into the muscle cells. Because its been recently killed these cells aren’t quite dead yet and can still respond to chemical stimuli. Some cells like nerve and muscle cells rely on ion channels to function. Sodium is one such ion that interacts with these cells.
So how does the squid “come back to life?”
The reaction is an automatic response to the sodium chloride, or salt, in the soy sauce. The recently deceased squid may lack a brain, but its muscle cells, which receive electrical commands, are still intact, NPR reports.
"Most of the tissue in an organism that’s recently dead, recently killed, is actually still alive" Charles Grisham, a chemistry professor at the University of Virginia, explained to Discovery News. “In this case, even though the brain function is missing, the tissues will still respond to stimuli.”
The squid’s muscles still retain Adenosine triphosphate (ATP), the main source of energy for muscle contractions. Therefore, when the sodium in soy sauce is absorbed into the creature’s body, it triggers muscle spasms that appear to make the cephalopod dance. Of course, a specimen must be fairly fresh for soy sauce to elicit this reaction, according to the report.