The jerking, kicking and flopping (of a just-butchered animal, a fish out of water).
What is that sound like a chicken jerking and flopping around?
To jerk and flop around (as an animal when slaughtered, a fish out of water, a chicken about to die from an illness, a person that has had hot water spilt on him, etc.). [Ngereg can be used interchangeably with ngowereg or pakowereg].
If there isn't anyone to hold that cow still, it will jerk and kick all over when it is butchered.
That crab is flopping around from being put on hot coals.