At first, the alien being — which is soon christened “Calvin” — appears to be an innocuous, inert singlecelled life form, visible only beneath a high-powered microscope.
Hugh can hardly contain his enthusiasm, though there are other crew members on board to take precautions, including Miranda North (Rebecca Ferguson, the most disciplined character in the motley ensemble), representing the Centers for Disease Control and Prevention — because nobody knows what Calvin is capable of, even after he’s attacked Hugh and face-hugged one of the other crew members.
As Miranda could attest, if Calvin turns hostile — and it doesn’t take long for that to happen — the entire crew should be prepared to sacrifice their lives in order to prevent the “symbiote” (to borrow the term used to describe Venom, even though Calvin never lingers long on a human host) from finding its way back to earth.
Instead, the characters — and Gyllenhaal’s David Jordan in particular — are so empathetic, they’re constantly opening hatches that should remain locked shut in order to save goner crewmates, or themselves.
On the plus side, such ill-advised and undisciplined behavior serves to boost the suspense considerably, and even though we can never quite get a handle on what Calvin can do — the invertebrate creature can instadigest an entire rat, withstand prolonged exposure to fire, go long stretches without oxygen, survive in subzero space, and propel itself through narrow apertures — one thing is clear: it ain’t friendly.