A submission to the Anatomically Correct series!
Yes, a man-sized pitcher plant would (probably) be realistic, and yes that would sure be a man eating plant.
But, this question is not asking about those man eating plants, it is about the fiction land, trope, man-eating plant, that usually look a lot like these:
These kinds of man eating plants are often portrayed as:
Something belonging in the Plantae Kingdom
That has humans as it primary food source,
Is big enough to eat its prey in one bite;
has a clear, bulb-like mouth (head?) part with lip, teeth and tongue like appendages sustained by a single stem;
Actively chase people that get close enough but can't uproot itself
Show a high level of awareness of its surroundings,
Are able quickly grow/ungrow vines to tangle their prey.
**Bonus (a scientific explanation for these happening is appreciated, but not required) **
Seem to produce "saliva" and/or growl
Show some sentience (ex: will use the vines to manipulate tools, block possible escape routes, rip tools of people's hands, identify threats)
Would a plant thing like that be able to realistically evolve? If so, what sort of environmental pressures would create it?