Sweet Tooth: What Is The Sick, Explained

By Klein Felt Posted:
Sweet Tooth Christian Convery as Gus

Since Season 1, The Sick played a major role in Netflix's Sweet Tooth series. 

Based on the DC Comics fantasy series of the same name, the streaming hit follows a young deer/boy hybrid named Gus who is growing up in a world plagued by a mysterious disease that is killing off humans. 

Season 3 marks the end of the Netflix epic, bringing a close to the story of Gus and the fantastical alternate future Earth he finds himself occupying. 

What Is The Sick in Netflix's Sweet Tooth?

A human suffering from The Sick in Sweet Tooth looking sickly with red rings around his eyes and sweat on his brow

After three seasons and 24 episodes, the threat of The Sick looms heavy over the Sweet Tooth series. 

This mysterious disease is at the heart of this DC Comics adaptation, plaguing humanity in a far-flung future. 

The Sick is an affliction (also known as H5G9 Virus) that is killing off humans en masse. However, with the emergence of the ailment also comes the arrival of a new human species known as hybrids. 

These hybrids are a mix of humans and animals, one of which is Gus, the show's central character. 

A baby hybrid with a big animal ear in Sweet Tooth

Curiously though, The Sick only seems to affect humans, with hybrids being somewhat immune to it. 

This causes most humans to turn their aggression toward the hybrid population, as they believe the half-human half-animal beings may be to blame for the arrival of the virus. 

The symptoms of The Sick start with the twitching of the pinky, leading to fever, coughing, red-rimmed eyes, and fatigue. Those inflicted with the disease are expected to die within three or four days of contracting it. 

One notable sign of The Sick is the growth of purple flowers in areas where people are infected with the malady, as it is revealed that they grow from the corpses of those who die from H5G9.

What Caused The Sick In Sweet Tooth?

Gus looking at the tree on fire in Sweet Tooth

Throughout much of Sweet Tooth, the source of The Sick is unknown. 

Some believe the cause of the mysterious disease is the newly emerged hybrid species, as they began to appear as the virus took hold. 

However, this has never been confirmed, and, in fact, is debunked during Season 3.

In Season 3 it is revealed that a tree was the one to blame for The Sick.

In Season 3, Episode 5, James Thacker (played by Joel Tobeck in the Netflix series) can be seen taking an axe to an antler-like tree with mysterious properties.

It is this flashback moment that becomes the catalyst for the pandemic that would go on to plague humanity.

Its sap seems to be ground zero with this swing of an axe being the moment that infected humans and created the hybrids. 

The series finale sees Gus and company burn this tree down, seemingly healing the hybrids and giving these half-human half-animal beings a future in the world. 

Sweet Tooth Season 3 is now streaming on Netflix. 

Read more about Sweet Tooth:

Will Sweet Tooth Season 4 Happen? Netflix Officially Confirms the Fate of the Series

Full Cast of Sweet Tooth Season 3 - Every Main Character & Actor Who Appears (Photos)

- About The Author: Klein Felt
Klein Felt is a Senior Editor at The Direct. Joining the website back in 2020, he helped jumpstart video game content on The Direct. Klein plays a vital role as a part of the site's content team, demonstrating expertise in all things PlayStation, Marvel, and the greater entertainment industry.