This made me jump the first time I saw it: sushi that's so fresh it's still alive!
This type of food is called Ikezukuri, or the preparation of sashimi (raw seafood) from a living animal. Wikipedia explains:
Ikizukuri usually begins with the customer selecting, from a tank in the restaurant, the animal (shrimp, octopus, lobster, assorted fish) they wish to eat. The chef, almost always a sashimi chef who has undergone years of training and apprenticeship, takes the animal out of the tank and filets and guts it, but without killing the animal, which is served on a plate, sliced, with the heart still beating.
Needless to say, this food preparation method is controversial. Many people consider ikezukuri as inhumane and needlessly cruel, whereas aficionados claim that the flavor, quality, and freshness justified the procedure.