I'll try to dial it up on youtube, that alpha male is moving toward the moron as soon as it sees him approaching the water, and those fuckers strike fast. most of these gifs get their start as a youtube video.
Found the YT video, but it only contained exactly what you see in the gif, but to satisfy your morbid curiosity (& mine) here's a video of 9 actual attacks on humans by crocs/gators.