disturbing creature spotted on channel 183

My 10 year old daughter spotted something on animal planet channel 183 on DSTV. there is an animal planet advert that was viewing a large school of fish being chased by a shark with a human like creature swimming between the fish past the shark that looked very disturbing and scary. The creature can easily be spotted when playing in slow motion. My daughter paused the advert by co incidents and asked me what it is. I don't know what to tell her. Animal Planet is supposed to view animals that really exist. Can someone please explain what my daughter saw.