This is must watch and small science fact. The Cuttle fish dish which is known as Odori Don . Here's a dead cuttlefish. Soy sauce is being poured on it. Soy sauce is very, very high in sodium. Sodium is responsible for a lot of the activity in nerves, so when you pour lots of it on the dead fish's nerves it flinches and spasms.
Here is the clip:
And the video :