I wouldnt be surprised if Drexchanged the color of texture of the tip of its tail to look like food for the herbivores. I dont think we'll see any humans being hypotized but maybe tricked by his camo.
I'm sure fish are more easily hypnotized than people but imagine if D rex could hypnotize people like David Blane then perform crazy tricks.
"Oh D!! I cant beleive D rex took that guys watch and wallet without him knowing!"