A ship comes into New York harbor and the police find it abandoned. It's discovered that it is carrying hundreds of green egg shaped things that when the insides make contact with the human body, the body will, within seconds, explode. That sets up the expected gore in this film.
Several investigators travel to South America and find that the eggs are coming from a huge one eyed alien being that grew from a small seed brought back from Mars by an astronaut. This is a weird but enjoyable film that Cozzi made to cash in on the chestbursting scene in "Alien".
The beginning and the last 25 minutes are the best and yes, the film does drag a bit in the middle, but it is worth staying with for the final payoff.