Imitation crab meat is made from starch and finely pulverized white fish (surimi).
The starch and white fish are pulverized and processed to make what resembles crab meat.
The crab meat is fish but not actually crab meat at all.
The imitation crab meat is a cheaper alternative to regular crab meat and is much easier to find.
The origin of imitation crab meat is Japan where they took or still take white fish Surimi and turn it into crab meat that is a cheaper alternative to real crab meat.
I've eaten imitation crab meat and it tastes pretty good and similar to real crab meat.
However real crab meat is the better crab meat.