I have seen California sea lions killing ocean sunfish (mola molas) in a way that appears to be sadistic, or at least just for sport. The sea lions bite the fishes' fins off without eating them, then play with the crippled bodies like living frisbees. After a while the sea lions get bored and let the fish sink to the seafloor where they're eaten alive by crabs.
Nature, red in tooth and claw.