Animals - Velociraptor

Scientific consensus: size of a turkey, feathered.
Hollywood depiction: size of an ostrich, featherless, and scientists are fucking idiots.

Rather unfortunate they didn't make the movie like, 2 years later. That's when they discovered the utah raptor which is much closer to the hollywood depiction of a velociraptor.
I believe one of the film peeps had an interview and was like "We imagined it, then they discovered it."