An international co-production between Ireland, Denmark, and Belgium, it stars Imogen Poots, Jesse Eisenberg, Jonathan Aris, and Éanna Hardwicke.

The film follows a couple (Eisenberg and Poots) who are forced to care for a mysterious humanoid creature while trapped in a strange, vivarium-like neighbourhood.

The opening scene depicts the brood parasitism of a cuckoo before introducing primary school teacher Gemma and her landscaper boyfriend Tom.

They drive to meet with real estate agent Martin and follow him to a suburban development of identical houses called Yonder.

One day the Boy goes missing and returns with a book of symbols and diagrams of humanoids with throat sacs.

When Gemma asks him to mimic the person who gave him the book, he makes rasping sounds and inflates his own throat sacs.

Gemma follows and crashes through a door into multiple rooms in other houses with more Boys and several strangers, one of whom has died by suicide.

The Boy zips Martin into a vacuum bag and puts him into a garbage chute disguised as a file drawer.

In May 2018, it was announced that Lorcan Finnegan would direct Vivarium from a story he co-wrote with Garret Shanley, and that Jesse Eisenberg and Imogen Poots had joined the cast.

[8][9] Shortly after, Saban Films and Vertigo Releasing acquired US and UK distribution rights, respectively.

The site's critics consensus reads, "Vivarium may confound almost as often as it intrigues, but this well-acted sci-fi/horror hybrid has interesting ideas—and explores them with style".