6. The Dumbest Biologist In The World - Prometheus
The Plot Hole: "Why is the man who is supposed to be the best biologist in the world also the dumbest person in the world? Phrased differently:
why did this intelligent person try to pet a ridiculously terrifying snake alien?"
The Deleted Scene: You know the part I'm referring to, don't you? How could you not? The character called Milburn in
Prometheus - who has been selected for the most important mission in the history of mankind, by the way - suddenly decides to approach an alien snake creature with the same temperament that one might approach a newborn kitten. It ends in him getting killed. Some of you might not think this is a plot hole, but I certainly do: how did somebody so stupid get selected for this? That notion alone renders the rest of the plot totally moot by default. And yet there's a deleted scene that explains Millburn's bizarre behavior during this scene (well, to a relative degree, anyway). Removed due to time constraints, it shows Millburn's awe and wonder over discovering a new species - in this case, a little eel-like creature, which he puts into a jar. Supposedly this scene was designed to show how excited the biologist gets when confronted with a new species, and also serves to explain why he lets his guard down and attempts to pet a snake. It doesn't excuse Millburn's idiocy entirely, but it at least
tries to.